The IPL impact player rule explained, and what it costs

Cricket spent most of its history insisting that a substitute could not do anything worth doing. Law 24 lets a fielding side bring on a replacement for a player who is injured or otherwise unable to continue, and that replacement may field. He may not bowl. He may not bat. He may not keep wicket unless the umpires allow it, and he may not captain the side. He is a pair of hands in the covers, borrowed for an hour, and the scorecard barely acknowledges he was there.

The impact player rule, which the IPL brought in for the 2023 season after trying it in India's domestic Twenty20 competition, throws that away. The substitute it permits is a whole player. He bats in whatever position the captain fancies, bowls a full allocation of overs, keeps wicket if that is his trade, and the man he replaces walks off and plays no further part in the match. Here is the impact player rule explained in a single sentence, and the sentence still understates it, because a provision that lets a side exchange a bowler for a batter halfway through a game is not really a substitution rule.

It is a selection rule that stays open after the toss.

That is the whole of it, and everything else in this article is a consequence. A captain used to make one irreversible decision about the balance of his side, in the dark, before he knew whether he was batting or bowling. Now he makes most of it in the dark and finishes it in the light, with the pitch read, the dew assessed and the target known. Cricket has spent a century and a half building its tactics on the assumption that you commit first and find out afterwards. One clause in a franchise league's playing conditions reversed the order.

A substitute who can bat and bowl is a new object in cricket

Take the three things cricket already had, and the impact player sits outside all of them.

The ordinary substitute under Law 24 fields and nothing more. He exists so that a side reduced by injury is not fielding with ten men, and the restrictions on him exist so that the substitution cannot be an advantage. A side cannot bring on a better fielder because the light has gone, station him in the deep for the last four overs and call it an injury. The Law is written to make the exchange neutral.

The runner was the batting equivalent and has been gone from international cricket since 2011. A batter who could stand but not run used a colleague to run for him, which produced a great deal of confusion at both ends and a steady supply of run outs that nobody could satisfactorily explain. It was removed because it was being used tactically, by batters whose cramp arrived at convenient moments, and because a rule that depends on an honest declaration of physical distress is a rule that will be gamed.

The concussion replacement is the closest existing thing, and the comparison is instructive because of how carefully it is fenced. It is a medical provision, it requires the match referee's approval, and the replacement is meant to be like-for-like, so that a side does not gain by losing a player to a blow on the helmet. The referee can impose restrictions on the incoming player to keep the exchange neutral. The whole apparatus exists to make sure a concussion is not an opportunity, and the tightness of that fence tells you how seriously cricket has historically taken the principle that eleven players start and eleven players finish. The way that protocol is designed, and why it is deliberately not tactical, is a subject of its own in the explanation of how a concussion replacement is approved and restricted.

The impact player belongs to none of those categories. It is not restitution for a loss, it is not medical, and it is not intended to be neutral. It is designed to confer an advantage on the side that uses it well, and that is what makes it a genuinely new object rather than a tweak. Cricket has plenty of rules that let you recover from misfortune. This is the first one that lets you change your mind.

• 11Players named in the starting eleven
• 5Substitutes named alongside them
• 4Overseas players allowed on the field
• 1Impact players a side may use

Values set by the IPL's published match playing conditions. The overseas limit applies to players on the field at any one moment, not to the squad.

The impact player rule explained, in the order the match runs it

The mechanics are simple once you put them in sequence, and the sequence matters more than the individual clauses, because the timing of each step is where the tactical value sits.

Before the toss, a captain prepares two elevens. This is the change that gets least attention and is nearly as significant as the impact player itself. The IPL allows a side to walk out with one team sheet for batting first and another for fielding first, and to hand over the relevant one once the coin has landed. Previously the sheets were exchanged before the toss and could not be altered, so a captain guessed at the conditions and the toss outcome together, and sometimes guessed wrong twice.

At the toss, the eleven and the substitutes are named in writing. Five substitutes go on the sheet alongside the starting eleven. The captain does not have to say which of the five he intends to use, or whether he intends to use one at all. Naming them all costs nothing and commits nothing, and it means the opposition knows what is available without knowing what is planned.

Only a named substitute can become the impact player. This is the clause that stops the rule becoming a free pick from the whole squad. If a side has left an out-and-out finisher off both the eleven and the list of five, he cannot be summoned when the chase goes wrong. The list is where the real selection happens, and a coach who fills it with three reserve fielders and two net bowlers has given his captain nothing to work with.

The swap happens at a break in play. The start of an innings, the end of an over, the fall of a wicket, or a batter retiring. A side cannot stop a match mid-over to fetch somebody, with the exception that a batter can come in at a fall of wicket, which is by definition mid-over half the time. A substitute who arrives part way through an over cannot bowl the balls remaining in it, which closes the obvious loophole of bringing on a fresh bowler to finish an over that has gone badly.

The door only swings one way. The player who is replaced is finished for the match. He does not come back at the innings break, he does not return as a fielder, and if he has already batted his innings stands. That permanence is what makes the decision a real one. If the exchange were reversible, every side would use it every match without thinking, and the rule would collapse into a rolling twelve-man free-for-all.

The window closes before the end of the innings. In a full twenty-over innings the substitution must be made by the end of the fourteenth over. Weather-shortened matches move the deadline earlier in proportion, and below a certain innings length the rule stops applying altogether, on the sensible grounds that a ten-over thrash does not have room for a mid-match reselection. The exact scaling is in the season's playing conditions and is worth checking rather than assuming, because the IPL has adjusted the details more than once.

1. 1Before the coin goes upBoth coaches prepare two elevens, one for batting first and one for fielding first, plus the five substitutes who will be named either way. The list of five is the real decision, because nobody outside it can be used later.
2. 2The tossThe winning captain chooses, both sides hand over the relevant sheet, and the eleven and the five become fixed. From here the only player who can enter the match is one of those five.
3. 3Innings one, the side batting firstIt may send in an extra batter at any break up to the end of the fourteenth over, usually by removing a bowler it does not expect to need. It is guessing at a par total, because nobody has chased on this pitch yet.
4. 4Innings one, the side fielding firstIt may bring on an extra bowler at the same points, typically to replace a lower-order batter who will not be needed in the chase. Most sides hold the option here, because the information gets better later.
5. 5The innings breakThe chasing side now knows the target, the pitch, the dew and which boundary mattered. This is the cheapest and best-informed moment in the match to make the swap, and it is where a great many of them happen.
6. 6Innings two, before the fourteenth overBoth remaining options expire here. A chasing side that is ahead can afford to hold its extra batter as insurance. A side that is behind has to spend the option to have any use of it at all.
7. 7After the fourteenth overTwelve players have been used, eleven remain on the field, and the last six overs are played by whoever is left. Whichever side extracted a role change from its substitute rather than a like-for-like replacement is the one that got value.

The sequence of decision points the rule creates. Timings are from the IPL playing conditions. What each side does with them is tactics, not rule.

Why the window shuts at the fourteenth over

The deadline looks arbitrary until you consider what the rule would be without it.

If a side could bring on its impact player at any point, the obvious use would be a death-overs specialist parachuted in for the last two overs of a chase, or a single hitter sent out to face the final six deliveries. The substitution would stop being a reselection of the side and become a bespoke solution to a specific situation, which is a different and much cruder thing. A team could carry a player whose entire function was to bowl the twentieth over, never bat, never field, and never be exposed to anything he was not good at.

Cutting the window off with six overs to go forces the substitute to play cricket. He has to bat through a phase rather than for a moment, or bowl in the middle overs as well as at the death. He is exposed to being got out, or to being hit, in circumstances he did not choose. That is a meaningful difference in the quality of the contest, and it is the strongest design decision in the whole rule.

It also protects the shape of the finish. The last six overs of a Twenty20 innings are the part of the format with the most settled tactical grammar, and dropping a fresh player into the middle of it would rewrite that grammar in ways nobody has thought through. The deadline keeps the endgame recognisable.

There is a quieter effect too. Because the window closes at the same point in both innings, the side batting second gets to make a fully informed decision and the side batting first does not. That asymmetry is baked in and it is not obviously fair, which is a theme that recurs.

The overseas constraint is the load-bearing wall

An IPL side may not have more than four overseas players on the field at any moment. The impact player rule does not change that number, and the interaction between the two is where most of the confusion sits.

Work it through. A side that starts with four overseas players in its eleven has used its entire overseas allocation, so its impact player must be Indian. A side that starts with three can bring on a fourth overseas player, provided he was among the five named. A side that starts with two has two overseas slots spare and can use one, though it has probably weakened itself to get there.

The consequence is a genuine strategic choice made at the toss. Do you play your four best overseas players from the first ball, and accept that your substitute must be a domestic player? Or do you start with three, keep an overseas match-winner on the bench, and hold the option of introducing him once you know what the match needs? Sides have gone both ways, and the second approach has become noticeably more common, because a top-quality overseas player held in reserve is worth more than the marginal difference between him and a domestic player over eleven overs of a first innings.

Without the four-player cap, the rule would be something else entirely. A twelfth slot with no nationality restriction would let a franchise field five overseas players across a match, which breaches the principle the cap exists to defend. That principle is that the IPL is an Indian competition, that its purpose includes producing Indian cricketers, and that a league where the best available players simply crowded out the domestic ones would win in the short term and hollow out the national side in the long one. The cap is not a compromise bolted on to the impact player rule. The impact player rule was designed around the cap, and the arithmetic only closes because the cap is there.

There is a second-order effect on the squad, which is that the value of a domestic finisher or a domestic death bowler rose sharply. If your impact player has to be Indian in most configurations, then the twelfth-best player in your side is drawn from the domestic pool, and franchises started paying for that accordingly. The way the market prices these constraints is the subject of the guide to how the IPL auction actually works, and the arithmetic there changed the moment the twelfth slot appeared.

Two uses, and why the extra batter wins

There are only two things to do with an impact player. Add a batter, or add a bowler. Both are legal, both are used, and they are not remotely equal in practice.

The extra batter. A side batting second removes a bowler who has finished his overs, or one it does not expect to need, and sends in an additional batter. The batting order that was seven deep becomes eight deep. Everybody above the change can play with more freedom, because the consequence of getting out has fallen. This is the dominant use of the rule and it is not close.

The extra bowler. A side bowling second removes a lower-order batter who is not going to be required, and brings on a fifth or sixth bowling option. This matters when a frontline bowler has been hit, when a match-up has gone badly, or when the surface has turned out to suit a bowler the captain left out.

Three things explain why the batting use dominates.

The first is information. A chasing side knows the target. Knowing the target converts a vague question about balance into a precise one about how much batting is needed to score a specific number off a specific number of balls, and the answer to that question is almost always "more batting". A bowling side making the same decision is guessing at what will be needed, and the natural response to uncertainty is to keep the option in your pocket.

The second is the shape of the value. An extra bowler adds four overs of a slightly better option than the alternative, which is a modest and bounded gain. An extra batter changes the risk tolerance of every player above him for the whole innings, which is not bounded at all. A side batting with a deeper order does not merely have one more wicket, it plays every ball differently, and the compounding effect of that across a hundred and twenty deliveries is larger than the effect of one better bowler across twenty-four. The mechanics of how a chasing side converts wickets in hand into scoring rate are worked through in the piece on pacing a run chase properly.

The third is that the bowling use is often unnecessary. A captain who needs a sixth bowling option usually has one already, in the form of a part-timer or an all-rounder, and the marginal gain from replacing that part-timer with a specialist is real but small. A captain who wants an eighth batter has no other way of getting one.

The result is that most impact player decisions are made at the innings break by the side batting second, and most of them add batting. A side batting first is making the same call with worse information, which is a real disadvantage, and one of the sharper counterarguments to the whole rule is that it hands an advantage to whoever wins the toss in a competition that already had a toss advantage.

A side that effectively fields twelve players

The phrase that gets used is "twelve-man cricket", and it is worth being precise about what it does and does not mean.

There are never twelve players on the field. The rule does not give a side an extra fielder, an extra wicket or an extra over. What it gives is a twelfth slot, which is a different resource, and one cricket had never previously offered.

The distinction matters because it tells you where the advantage actually appears. It does not appear in the field, where a side is still spreading nine outfielders around a boundary that has not moved. It appears in selection. A captain choosing eleven players had to solve a constraint problem: five bowlers, six batters, a keeper, and eleven bodies to fit them into, which does not work unless somebody does two jobs. A captain choosing eleven plus one solves an easier problem, because the twelfth slot absorbs the overlap.

• Conventional eleven
• With an impact player

Specialist batters56

Wicketkeeper11

All-rounders20

Frontline bowlers35

An illustrative composition showing where the extra slot goes, not the eleven of any particular franchise. The left figures total eleven, the right total twelve.

Show the numbers

A constructed side, before and after the twelfth slot

Item	Conventional eleven	With an impact player
Specialist batters	5	6
Wicketkeeper	1	1
All-rounders	2	0
Frontline bowlers	3	5

Read the two columns and the effect is plain. The all-rounders have not been replaced by better all-rounders. They have been dissolved into a specialist batter and a specialist bowler, because the slot that used to force the compression no longer exists. That is not a coaching preference. It is what an optimising selector does the moment a constraint is relaxed.

33%25%25%17%

• Top order, including the keeper4
• Middle order and finisher3
• Frontline seamers3
• Spinners2

A constructed breakdown of the same twelve slots by job rather than by discipline, to show that no role has been added, only unbundled.

Show the numbers

The twelve roles a franchise now fills for one match

Item	Value
Top order, including the keeper	4
Middle order and finisher	3
Frontline seamers	3
Spinners	2

The reason this feels bigger than it sounds is that eleven is not just a number in cricket. It is the constraint that generated most of the sport's interesting selection problems. Whether to play the extra bowler or the extra batter, whether to trust a keeper who bats at six, whether a second spinner is worth the tail he creates: those questions existed because the number was eleven and could not be twelve. Change the number and the questions do not become harder. They stop being asked.

What the impact player rule does to the all-rounder

This is the part of the argument that actually matters, and most coverage of it stops at the observation that all-rounders are unhappy.

Start with why an all-rounder was valuable in the first place. It was never simply that he could do two things. It was that he could do two things in one slot, at a moment when slots were the scarcest resource on the team sheet. A player who batted well enough to come in at seven and bowled well enough to get through three overs of a Twenty20 innings was not being paid for the sum of those two abilities. He was being paid for the third thing they created between them, which was a free place elsewhere in the eleven.

That free place is worth a lot. It might be an extra specialist spinner on a turning pitch, or a fourth seamer, or a batter who would otherwise have been carried at eight. Whatever it bought, the all-rounder bought it, and his price reflected that. He was priced off the constraint, not off his output.

Now relax the constraint. If a side can carry a specialist batter and a specialist bowler in the space that used to hold one player who did both, then the free place has already been created by the rule, and nobody needs to buy it from the all-rounder. What he is left selling is his batting, judged against specialist batters, and his bowling, judged against specialist bowlers. In both comparisons he is by definition second best, because that is what being an all-rounder means. His value did not fall because he got worse. It fell because the thing he was uniquely supplying is now supplied by a clause in the playing conditions.

That is a market mechanism rather than a grievance, and it is the reason the complaint has come from senior players rather than from statisticians. Anyone who built a career on being the solution to a problem watches the problem get abolished with mixed feelings.

There are three serious counterarguments, and they are stronger than they are usually given credit for.

Insurance still has value. The impact player is a one-way door and there is only one of them. If a frontline bowler pulls up mid-spell after the substitution has been used, the captain needs somebody in the remaining eleven who can bowl. If a top-order batter is hurt fielding, the same logic applies in reverse. A side made entirely of specialists is brittle in a way a side with two genuine all-rounders is not, and the failure mode is not a slightly worse outcome. It is four overs handed to somebody who does not bowl.

The best all-rounders were never marginal. A player who is genuinely front-rank at both disciplines is not competing for the seventh slot. He would be in the side for either skill alone, and the second skill is pure surplus. The rule compresses the value of the ordinary all-rounder, the useful cricketer who is a solid seven and a fifth-bowler option, far more than it touches the rare one. That distinction is real and it gets lost in the general lament.

Overs still have to come from somewhere. Twenty overs, four each, five bowlers minimum. A side that fields six specialist batters plus a keeper has to find those overs from five men, none of whom can have an off day, because there is no sixth option to hide behind once the substitution is spent. Sides that have gone hardest at the specialist model have discovered that a bowler being taken apart in his second over is a problem with no solution.

The deeper worry is developmental rather than tactical, and it deserves stating plainly. Domestic cricket in India feeds the national side, and the IPL is the most visible and best-paid part of that pipeline. If a twenty-year-old batter observes that the way into a franchise side is to be the best pure batter available, he will spend his practice hours on batting. The bowling he might have developed into a genuine second skill does not get developed, because nothing in his environment rewards it. Ten years later the national selectors, picking for international cricket which has no impact player rule, go looking for a batting all-rounder and find the production line has stopped making them.

That is a slow, invisible cost, and it is the one honest argument against the rule that cannot be answered by pointing at a scoreboard. It also cannot be proved for years, which is precisely why it is dangerous. The broader question of what an all-rounder is actually worth, and how badly the standard statistics measure it, is taken apart in the analysis of why all-rounders are priced the way they are.

Does it inflate scores, or does it produce closer finishes?

Both claims are made, usually by the same people about the same matches, and both have a mechanism behind them.

The inflation argument runs like this. A batting side with an extra batter has a shorter tail, so the cost of a wicket falls, so batters take risk earlier and more often. Risk taken earlier in a Twenty20 innings raises the expected total, because the deliveries being attacked are the ones with fielders inside the circle. The tail that used to arrive at number eight and terminate the innings now arrives at number nine or not at all. The bowling side loses the two or three soft wickets that used to convert a good position into a decisive one. Every link in that chain is a genuine consequence of the rule, and none of it requires a single statistic to follow.

The closer-finishes argument runs the other way, and it depends on both sides having the same tool. If the side batting first uses its extra batter to post a bigger total, and the side batting second uses its extra batter to chase it, then par has risen for both and the margin has not necessarily moved. What has changed is that the chasing side can keep attacking deeper into the innings, because it has more wickets to spend. Chases that would previously have died in the fifteenth over, with the required rate climbing and two recognised batters left, now stay alive to the eighteenth. A match that stays alive longer is a better match, whatever the total says.

The honest position is that both are true and they describe different things. Higher scores and closer finishes are not opposites. A competition can perfectly well produce more runs and more tight endings at once, and the two arguments only conflict if you assume the entertainment value of a match is a function of its total, which nobody who has watched a low-scoring thriller believes.

The sharper criticism is a third one that gets made less often. The rule increases scoring by reducing the number of ways a bowling side can win. An attack that bowls well and takes six wickets used to be rewarded with a collapse, because the seventh, eighth and ninth wickets came cheaply behind it. Now the reward is smaller, because behind the sixth wicket stands a batter who would have been in the side on merit anyway. Bowlers have not been made worse at bowling. The consequences of doing it well have been trimmed, and a format that trims the consequences of good bowling is quietly changing what it is a contest between.

The objection that it deletes the captain's hardest decision

Picking the balance of a limited-overs side is the oldest and best argument in cricket, and it was a genuinely hard problem because it had no correct answer.

Play the extra bowler and you bat too shallow, so one collapse ends you. Play the extra batter and you are a bowler short, so one bad spell ends you. Split the difference with an all-rounder and you have a player who is worse than the specialist at both jobs. There is no arrangement of eleven cricketers that is not exposed somewhere, and the skill of captaincy in white-ball cricket consisted very largely of choosing which exposure you could live with on this pitch, against this opposition, on this day.

The impact player rule does not solve that problem. It removes it. A captain who does not have to choose between the extra bowler and the extra batter is not exercising judgement, he is filling in a form, and the moment where a career could be defined by a call made an hour before the toss has been quietly deleted.

Two smaller losses come with it, and both are the sort of thing that only becomes obvious once it is gone.

Hiding a bowler is no longer a skill. A captain with a fifth bowler he did not trust used to conceal him: two overs in the powerplay when the field was up and the batter was still setting himself, then two more against a left-hander who could not hit him, or not at all if the match allowed. Getting those four overs out of a weak link without losing the match was a real and watchable piece of captaincy. Now the weak link is substituted.

The part-timer is disappearing. The batter who bowled three tidy overs of off spin because somebody had to was a fixture of limited-overs cricket for fifty years, and he existed only because the eleven-player constraint made him necessary. Take away the necessity and he stops being selected, then stops being developed, and eventually stops existing. Something small and specific goes out of the game with him.

Set against all that is the defence, which is not nothing: a rule that produces a better contest on the field is worth more than a rule that produces a better argument in the pavilion. The counter to the counter is that the argument in the pavilion was the contest, or at least a large and beloved part of it. Reasonable people are still shouting at each other about this, which is usually a sign that a rule has changed something real.

What it did to the auction and the shape of a squad

The squad-building consequences are large enough to have their own logic, and they mostly reduce to a single sentence: a franchise now buys twelve players for a match rather than eleven, and the twelfth is not a reserve.

That changes what a squad is for. The bench used to be insurance, filled with players who would appear if somebody was injured or out of form. Now a defined portion of it plays in most matches, which means those players have to be good enough to face a Twenty20 attack or bowl at a set batter, and they have to be bought accordingly. The cheap squad filler has less of a place, and the specialist who does one thing extremely well and nothing else has much more of one.

It also changed which players a franchise will spend heavily on, because the impact player slot is often the natural home for an expensive specialist whose limitations would have kept him out of a conventional eleven. A batter who cannot field and does not bowl is a liability in an eleven-man side and a perfectly reasonable purchase in a twelve-slot one. How franchises weigh those calls against the auction purse, and against the players they have already committed to, is set out in the walkthrough of how retention constrains a squad before bidding starts. Both of those pieces cover the market mechanics properly, and the point here is only that the impact player rule is one of the inputs to them rather than a separate subject.

The other quiet effect is on overseas recruitment. A franchise that intends to start with three overseas players and hold the fourth in reserve is buying a different sort of overseas player from one that intends to start with four, and it is buying more domestic depth to go with them. Squad shape follows the rule, and the rule is only a few seasons old, so squad shape is still moving. Anyone tracking the wider franchise circuit will notice that squads built for the IPL are now visibly different from squads built for leagues without the rule, which is as clean a natural experiment as this sport ever offers.

Should other competitions use the impact player rule?

The IPL is not the only competition to have tried a tactical substitution, and the comparison is useful because the others drew the line in different places.

The Big Bash has run a narrower version, in which the substitute can only replace a player who has barely been used, with the swap available at a defined point in the match. The effect is that a side names a twelfth player whose entry is conditional rather than free, and cannot simply exchange a spent bowler for a fresh batter at the innings break. It is a smaller rule doing a smaller job, and Cricket Australia publishes the current conditions, which are worth reading directly rather than assuming they match the IPL's. Differences of that kind are exactly what gets flattened in general coverage, along with the fact that the domestic competitions have been diverging from each other for a decade, something the guide to the format the Big Bash actually plays goes into.

International cricket has not adopted it, and the reasons are worth stating because they are not merely conservatism.

An international side is picked from a national pool rather than bought at an auction, so the twelfth slot would advantage the deepest countries by more than it advantages anyone else. Bilateral series are played under ICC playing conditions meant to be stable across decades, and a rule that reshapes selection is a large thing to introduce to a format whose records are compared across generations. Most of all, the international calendar is built on players who move between formats, and a rule that stops producing all-rounders in the domestic Twenty20 game is a rule that eventually costs the Test side, which is a price a national board pays and a franchise does not.

The general principle worth carrying away is that a substitution rule is a competition-level design choice rather than a law of cricket, and it should be judged against what that competition is for. A franchise league selling three hours of television has different objectives from a bilateral Test series, and there is no reason both should reach the same answer. What is unreasonable is assuming the IPL's answer is the default. The IPL, the other domestic leagues and the international game each publish their own playing conditions, and the only reliable way to know whether a substitution is available in a match you are watching is to read the ones that govern it.

What a fairer version might look like

If the objection is that the rule removes a decision, the fix is not to remove the rule. It is to put a decision back into it. Four adjustments would do that, in increasing order of how much they change.

Name the impact player at the toss. As it stands, both sides know the list of five but neither knows the choice, and the side batting second gets to make its choice with the first innings behind it. Requiring both captains to name their intended substitute at the toss, before the coin goes up, would restore the symmetry. Each side would be committing to a plan in the dark, which is what the eleven used to require, and the substitution would become a bet rather than a correction.

Make it cost something. A side that uses its impact player could concede something measurable in exchange: an over from its bowling allocation, or a fielder kept inside the circle for two overs after the substitution, or the loss of a review. Any of those would convert a free option into a priced one, and a priced option is used thoughtfully. The current version is free, and a free option is always taken.

Cap what the substitute can do. Allowing the impact player two overs rather than four, or restricting him to batting only, would keep the rule's flexibility while stopping it from fully replacing an all-rounder. If a captain who wants six bowling options still has to find part of the sixth from within his eleven, the ordinary all-rounder recovers most of his value overnight, and the developmental worry largely goes away.

Turn the slot into a development slot. Reserving the impact player for an uncapped or under-23 player would take a rule currently criticised for narrowing the talent pipeline and point it at the opposite outcome. Every franchise would field a young Indian player in most matches, in a real match situation rather than a token one, and the competition would be producing cricketers as a by-product of its own tactics. This is the most interesting of the four and the least likely, because it costs franchises match-winning quality in exchange for a benefit they do not personally capture.

None of these is obviously right. What they have in common is that each one restores a trade-off, and a rule with a trade-off in it is a rule that rewards thought. The version the IPL currently runs is close to a free upgrade for whoever is chasing, and the criticism it attracts is not really that it changed cricket. It is that it changed cricket without asking anybody to pay for it.

Read the team sheet, not the scoreboard

Four things are visible before a ball is bowled, and together they tell you most of what each side intends.

Count the overseas players in the eleven. Four means the impact player will be Indian and the substitution is probably a batting one. Three means an overseas match-winner is being held back, and the captain has told you he expects to need him.

Look at who is named among the five substitutes. Two reserve fielders and three net bowlers is a side that does not plan to use the rule. A specialist finisher and a wrist spinner is a side that has already decided which of two matches it is prepared to play.

Note which side won the toss and what it chose. The chasing side holds the better-informed option, and the innings break is when it will use it. If the team batting first has not made its swap by the tenth over, it has probably decided to save its bowler and take the total it can get.

Watch the fourteenth over of each innings. After it, the sides are what they are, and the last six overs will be played by whoever is on the field. A captain who arrives at that point still holding an unused substitute has either judged the match perfectly or wasted his best option, and the scoreboard usually tells you which within about three overs.

Get into that habit and the rule stops being an oddity of one competition and becomes what it actually is, which is the largest change to how a cricket team is picked since the limited-overs game was invented. The tournament that introduced it is the place to watch it operating, and the rest of the tactical vocabulary it interacts with sits in the cricket section of this site.