Running Back vs Fullback: Who Carries and Who Blocks
Running back vs fullback in the NFL: the halfback or tailback carries the ball, the fullback lines up ahead of him and blocks. The names predate both jobs.
By CricketTaken EditorialPublished Updated NFL Positions & Schemes21 min read
- Backs on the field in 21 personnel
- 2
- Jim Brown's NFL rushing titles
- 8 in 9 seasons
- Lorenzo Neal's streak blocking for 1,000-yard rushers
- 11 seasons
- Single-season carries record
- 416, Larry Johnson, 2006
For eleven straight seasons, from 1997 through 2007, whichever NFL team employed Lorenzo Neal had a 1,000-yard rusher. It was never Neal. He was a fullback, which by his era meant lining up a few yards in front of the man with the ball, running into a linebacker at full speed, and letting somebody else collect the yardage.
That is the difference in one line. A running back and a fullback are both backs, both stand behind the quarterback, and both are running backs as far as the roster sheet is concerned. But the running back, who is also called the halfback or the tailback, is there to carry the ball, and the fullback is there to block for him. In the modern NFL the first is on the field for nearly every offensive snap and the second is a part-time specialist that some clubs do not carry at all. The rest of this page explains how two positions with such similar names ended up with such different work.
The difference between a running back and a fullback, job by job
The rulebook is no help here. To the NFL's playing rules both men are simply backs: players lined up at least a yard behind the line of scrimmage, wearing eligible numbers, allowed to take a handoff or catch a pass. Everything that separates them is coaching.
| Point of comparison | Running back (halfback, tailback) | Fullback |
|---|---|---|
| Main job | Carries the ball | Blocks for the ball carrier |
| Where he lines up | Deepest in the backfield, or beside the quarterback in the shotgun | Between the quarterback and the running back, or offset to one side |
| Touches | The most on the team after the quarterback | A handful a game, often none |
| In the passing game | Checkdowns, screens and routes out of the backfield; picks up blitzers | Extra pass protector; short routes to the flat |
| Short yardage | The usual choice | The dive straight ahead, when a team wants a quick hit |
| Time on the field | Close to every snap, shared among two or three players | A minority of snaps; none on teams without one |
| Special teams | Kick returns, for some | Coverage and blocking units, almost always |
One vocabulary point clears up most of the confusion. "Running back" has two meanings. As a position group it covers every back who is not the quarterback, fullbacks included, and a team's running backs coach handles both. As an everyday word it means the ball carrier. When an announcer says a team "has three running backs active," the fullback may or may not be one of the three. Where both sit among the other spots on offense is laid out in our guide to all the NFL positions.
Why the names seem backward
A fullback stands closer to the line than the halfback behind him. Anyone who has stopped to think about the words has noticed that this is the wrong way around.
The names are not about today's alignment. They come from the 1880s, when American football was pulling away from rugby and kept rugby's habit of naming backs by depth. The man who took the ball from the center stood a quarter of the way back. Two halfbacks stood halfway. The fullback stood behind everyone, the last man, and he was often the punter and the last line of defense in a game where everybody played both ways.
In the early T-formation that followed, the three deep backs lined up across, with the fullback in the middle directly behind the quarterback. He was the biggest of them and got the straight-ahead carries, the plunges into the line that made up much of the offense. So for the first half-century of the sport the fullback was a feature runner and frequently the feature runner. Bronko Nagurski of the Bears, the dominant power back of the 1930s, was a fullback. So was Cleveland's Marion Motley a decade later.
What flipped the picture was the I-formation. Tom Nugent is generally credited with introducing it at Virginia Military Institute around 1950, and John McKay's Southern California teams of the 1960s made it famous. The I stacked two backs in a line behind the quarterback and gave the ball to the deeper one, who had seven yards to read the blocking before he reached the line. The back in front of him became an escort. Coaches kept the old word for the bigger man, and the fullback found himself standing in the halfback's former spot with a blocker's job.
Halfback, tailback, running back
These three are the same player. Halfback is the T-formation word. Tailback describes the back at the tail of the I, and before that the deep man in the single wing who took the snap directly. Running back is the modern catch-all, and most NFL depth charts print it as RB and leave it there. Nobody is wrong for using any of them.
The ball carrier's craft
Carrying the ball looks like the simplest job in football: take it and run where the defenders are not. The players who last do four things that are hard to see on a broadcast.
Pressing the hole. A runner who cuts too early tells the linebackers where he is going while they can still get there. Good backs run directly at the designed gap for as long as they can, which forces the linebackers to commit to it, and only then make their move. Coaches call this pressing the line or pressing the hole. It takes nerve, because it means running toward traffic on purpose.
The cutback. Many running plays are designed with more than one possible lane, a point our explainer on the zone blocking scheme covers in detail. The line moves sideways in unison, the defense flows with it, and the runner's job is to find the crease that opens behind the flow and plant one foot to get through it. One cut, then upfield. Backs who dance get tackled for losses.
Pad level. The lower man wins a collision. A runner who arrives at contact with his shoulders down presents a smaller target and falls forward, and the difference between falling forward and being stood up is roughly two yards a carry over a season.
Ball security. Coaches teach contact points: the fingertips over the nose of the ball, the palm, the forearm, the bicep and the chest, with the ball carried high and tight to the body and switched to the arm away from the nearest tackler. A back who fumbles stops playing, whatever else he can do.
Then there is vision, which is the word scouts reach for when they cannot quite say why one back gains five yards on a play that gets another back two. It is partly anticipation, knowing how a block will turn out before it does, and partly patience. The individual plays those skills are applied to, from power to counter to the draw, are described in our guide to football running plays.
What a fullback does: four assignments
A fullback's playbook is short and violent. Nearly everything he is asked to do falls under four headings.
The lead block on an isolation play
The isolation, or "iso," is the oldest play in the I-formation and the purest statement of the job. The offensive line blocks every defender near the point of attack except one linebacker, who is left alone on purpose. That linebacker belongs to the fullback.
- The snapThe fullback fires straight at the gap between guard and tackle from about four yards deep. He does not wait for the handoff.
- The linemenEach blocks the defender in front of him, moving the defensive tackles sideways and leaving one linebacker unblocked.
- The collisionThe fullback meets that linebacker in the hole, shoulder under the linebacker's pads, and tries to turn him one way or the other.
- The readThe tailback, two or three yards behind, runs at the fullback's back and cuts off whichever way the block goes.
- The second levelIf the block holds, the runner reaches the safeties with a head of steam and a lineman or two still out in front.
A generic strong-side isolation from the I-formation. Blocking rules and the hole number differ from playbook to playbook.
The play is a referendum on one block. If the fullback wins it, the gain is five yards or more. If the linebacker wins, the runner has nowhere to go.
The kick-out on power
On the power play a guard from the far side of the formation pulls behind the center and leads through the hole. Someone has to clear the edge for him, and that is the fullback. He runs at the last defender on the line, usually a defensive end or an outside linebacker, and drives him toward the sideline. The runner goes inside that block and follows the guard.
The dive
Third and one. The fullback takes a handoff almost immediately after the snap and hits the line before the defense can react. There is no deception in it. Its merit is speed, because he starts closer to the line than the tailback does. In option offenses such as the wishbone, which Emory Bellard installed at Texas in 1968, the fullback dive is the first of the three options on the base play, the triple option, and the fullback piles up carries.
The flat route
Fake the handoff, roll the quarterback out, and the fullback slips into the flat a few yards past the line toward the sideline. It is a short, safe throw to a player the defense has stopped watching. Add ordinary pass protection, where he stays in to block a blitzing linebacker, and that is nearly the whole job on passing downs.
The running back in the passing game
A running back who can only run is half a player in the modern league. On passing downs he has two possible assignments, and he often does not know which until the ball is snapped.
The first is protection. The back is the last blocker. He scans from the inside out for a blitzing linebacker or safety, steps up into the pocket, and takes on a man who has had a ten-yard running start. If nobody comes, he releases late as an outlet. Getting this wrong puts a free rusher on the quarterback, which is why rookies with obvious running talent sometimes sit on third down for months. The arithmetic of extra rushers that makes the job necessary is set out in our piece on blitz packages.
The second is catching the ball, and the routes have their own names.
- The checkdown. A short route in front of the quarterback, thrown when everything downfield is covered. Unglamorous, and the source of a large share of a back's receptions.
- The screen. The linemen let the rush come, then slip out in front of the back, who catches a short pass behind a wall of blockers. Our explainer on the screen pass walks through the timing.
- The swing and the wheel. The back runs toward the sideline. On a swing he catches it there. On a wheel he turns upfield along the boundary, and a linebacker who was covering him for a short pass is suddenly in a footrace.
- The angle route. He starts toward the flat, plants and breaks back inside across the linebacker's face. Against man coverage it is the hardest of the group to defend.
The backs who did both jobs at the highest level changed how the position was valued. Roger Craig of San Francisco, in 1985, became the first player to gain 1,000 yards rushing and 1,000 receiving in the same season. Marshall Faulk matched it with the Rams in 1999 and Christian McCaffrey with Carolina in 2019. Craig, it is worth knowing, spent the early part of his career listed at fullback.
Fullbacks have had their moments as receivers too. Larry Centers, a fullback for the Arizona Cardinals, caught 101 passes in 1995, the first time any back had reached a hundred in a season.
Types of running back, from power back to bell cow
The vocabulary for ball carriers sorts them by build and by when they play. A depth chart rarely prints these labels, but coaches build their rotations around them.
| Label | What it means | The kind of player it describes |
|---|---|---|
| Power back | Runs between the tackles and through contact | A heavy runner such as Jerome Bettis or Earl Campbell |
| Scatback | Small, quick and hard to tackle in space | A back of Darren Sproles's size and style |
| Change-of-pace back | The second runner, chosen to contrast with the starter | A speed back behind a power back, or the reverse |
| Third-down back | Plays on passing downs for his protection and his hands | A receiver and blocker first, such as Kevin Faulk in New England |
| Short-yardage or goal-line back | Enters for a yard or less | Often the team's biggest runner, sometimes the fullback |
| Bell cow | An every-down back who takes the great majority of the carries | Emmitt Smith in Dallas, LaDainian Tomlinson in San Diego |
Two of the terms deserve a note. "Change of pace" is literal: a defense that has spent three series bracing for a 230-pound runner has to adjust its angles when a 195-pound one comes in, and the adjustment takes a few plays. And "bell cow," a farm term for the animal the herd follows, has become rarer in fact than in conversation. A back who plays all three downs and both the run and pass games is carrying a load that most teams now split.
Tomlinson's 2006 season shows what the every-down back could be at the peak. He ran for 28 touchdowns, a single-season record that stood through the 2025 season, and did it running behind Lorenzo Neal.
Where each lines up, and what the alignment gives away
Backfield alignment is one of the few things a defense can read before the snap with any confidence. Where the backs stand limits what the offense can run well.
| Alignment | Where the backs are | What it tends to signal |
|---|---|---|
| I-formation | Fullback about four yards behind the line, tailback about seven | Downhill running to either side, and play-action off it |
| Offset I | Tailback deep, fullback shifted toward the strong or weak side | A run toward the fullback's side, or a quick lead away from it |
| Singleback | One back behind the quarterback, no fullback | Balanced; the extra player is a tight end or a receiver |
| Split backs | Two backs side by side behind the guards | An older pro look, good for protection and quick passes to either back |
| Shotgun sidecar | One back standing beside the quarterback | Pass first; on runs the back usually crosses the quarterback's face |
| Pistol | Quarterback a few yards deep, back directly behind him | A shotgun view for the passer with a downhill path for the runner |
The offset I is the most talkative of these. A fullback set to the tight end's side is one step closer to a kick-out block there, and linebackers lean accordingly. Offenses know it, and run the lead play the other way just often enough to keep them honest.
The sidecar position has its own tell. A back standing to the quarterback's left is in a natural position to take a handoff going right, and to protect the left side on a pass. Defensive coaches chart those tendencies every week. The pistol, which Chris Ault developed at Nevada in 2005, was partly an answer to that problem: with the back directly behind the quarterback, the defense cannot tell from his position which way the run is going.
The wider family of sets these fit into, from trips to bunch, is covered in our guide to offensive formations.
Why the fullback faded from the NFL's base offense
Nothing was done to the fullback. No rule removed him. A third wide receiver took his place on the field.
Coaches describe who is in the game with a two-digit code: the first digit is the number of backs, the second the number of tight ends, and whatever is left over from five eligible players is wide receivers. The traditional pro offense was 21 personnel, with two backs, a tight end and two receivers. The offense the league uses most now is 11, with one back, one tight end and three receivers. Our page on personnel groupings explains the code in full.
The reasoning behind the shift is hard to argue with. A slot receiver forces the defense to take a linebacker off the field and replace him with a smaller defensive back, or else to cover a receiver with a linebacker. Either result helps the offense, including its running game, since a nickel back is easier to block than a linebacker. A fullback forces nothing. The defense simply keeps its base personnel on the field and matches him.
Rule changes pushed in the same direction. The NFL's 1978 limits on contact with receivers, and the steady tightening of pass-defense rules since, made throwing more efficient, and a team that throws on most downs has less use for a lead blocker. By the 2000s the shotgun was spreading too, and a quarterback standing five yards deep leaves no natural place for an I-formation behind him.
So the fullback went from starter to specialist. On most teams that keep one, he plays a minority of the offensive snaps and earns his roster spot partly on kickoff and punt units. A number of clubs in any given season list no fullback at all.
That may be a mistake at the margins. The teams that have kept a good fullback and built a running game around him have tended to run the ball very well, precisely because defenses now practice against him so rarely. Scarcity has made the position odd, and odd is useful.
Who does the job now: the H-back, the motioning tight end and the extra lineman
The lead block did not disappear with the fullback. Someone else throws it.
The H-back. Joe Gibbs built his Washington offense of the early 1980s around a single running back and replaced the fullback with a second tight end who lined up a step off the line and moved before the snap. That player, the H-back, could block like a fullback from a moving start, set the edge like a tight end, or release into a route. He gave the offense a lead blocker without telling the defense where the block was coming from.
The tight end in motion. The current version is a tight end who starts on one side of the formation, motions across behind the line and arrives at the snap to block the backside end or lead through the hole. It is a fullback's kick-out block thrown by a player the defense also has to cover as a receiver. What else that position is asked to do is the subject of our guide to the tight end.
The extra lineman. Near the goal line some teams bring in a sixth offensive lineman, who reports to the referee as an eligible player, or put a defensive tackle in the backfield. The best-known case is William Perry, the Chicago Bears' 300-pound-plus defensive tackle, who lined up as a fullback during the 1985 season and scored a touchdown in Super Bowl XX.
None of these players is listed as a fullback, and all of them are doing a fullback's work. The role turned out to be more durable than the roster spot.
Size and build
The two positions are built for different collisions. A running back takes his hits from the side and from below, from tacklers trying to wrap his legs, and needs to stay on his feet. A fullback delivers his hits head on, against a linebacker who has seen him coming for four yards.
A typical NFL running back stands somewhere between five foot nine and six feet and weighs 200 to 225 pounds. Being short is no handicap. A lower center of gravity helps balance, and a back who is hard to see behind a wall of six-foot-five linemen has a half-step on linebackers trying to find him.
Fullbacks run about six feet to six foot two and 235 to 255 pounds. That is linebacker size, which is the point, since linebackers are who they block. Put a fullback next to an offensive guard and he looks like the guard's younger brother: the same thick neck, low hips and short-area power, on a frame sixty or seventy pounds lighter and quick enough to reach a moving target.
These are ranges drawn from how the league generally looks, and neither position has a size rule. Jim Brown played fullback at around 230 pounds and outran defensive backs. The category has always had room for exceptions.
Running back by committee
Coaches once handed one back the ball 25 times a game and thought nothing of it. Most now divide the carries among two or three, an arrangement known as running back by committee.
- 416Most carries in a season: Larry Johnson, 2006
- 4409Most carries in a career: Emmitt Smith
- 18355Most rushing yards in a career: Emmitt Smith
NFL records as they stood through the 2025 season. Career and single-season totals can be passed, though none of these has been seriously approached in recent years.
Three things drove the change. Specialization is the first: if one back is the better runner and another the better pass protector, playing each in his best situation beats asking one man to do both. Freshness is the second. A back with eight carries in the fourth quarter is running against linebackers who have played fifty snaps.
The third is wear. Running back is generally regarded as the position with the shortest careers in the sport, and the reason is simple arithmetic. A back is tackled on almost every play he is involved in, usually by more than one defender, and a 300-carry season means absorbing that several hundred times. Production at the position tends to peak early and drop quickly, and front offices have responded by spreading the load and by declining to pay heavily for a back's later seasons. The all-time lists, covered in our page on the NFL's career rushing leaders, are dominated by players who were both great and unusually durable, which is a way of saying they are dominated by exceptions.
Larry Johnson's 416 carries for Kansas City in 2006 remain the single-season record. He never came close to that level of production again, and his season is the one most often cited by those who argue that a workload past a certain point takes something from a back that he does not get back. The evidence for a precise threshold is thin. The general direction is not seriously disputed.
When the fullback was the star
For most of the NFL's first sixty years, the best runner on a team was as likely to be its fullback as its halfback.
Jim Brown. Cleveland's fullback from 1957 through 1965 led the league in rushing in eight of his nine seasons and retired with 12,312 yards, then the career record, without missing a game. He was listed at fullback and ran like nothing the league had seen: the power of the position's tradition with a sprinter's speed.
Larry Csonka. The fullback of Miami's early-1970s teams ran behind a line that pulled and trapped, and he was the centerpiece of an offense that threw as little as it could get away with. In 1972, the unbeaten season, he and halfback Mercury Morris each gained 1,000 yards, the first teammates to do so. He was the Most Valuable Player of Super Bowl VIII with 145 yards.
John Riggins. The edge case, and an instructive one. Riggins had a fullback's body, around 230 pounds, and was listed at fullback early in his career with the Jets. In Washington he was the lone back in Gibbs's one-back offense, with H-backs doing the leading. His 166 yards in Super Bowl XVII, including a 43-yard touchdown run on fourth and one, came from a big back carrying the ball in an offense that had just abolished the blocking fullback.
After Riggins the line of ball-carrying fullbacks thins out. The men who defined the position from the late 1980s on were blockers. Neal is the standard: Jets, Buccaneers, Titans, Bengals and Chargers in succession across those eleven seasons, a different runner behind him at most stops, and the same result each year. He was chosen for Pro Bowls on the strength of plays in which he never touched the ball, which is as good a summary as any of what the fullback became.
The more recent fullbacks who have drawn attention are a third type again, used as blockers, short-yardage runners and receivers out of a dozen alignments, closer to the H-back than to Csonka. The name has now covered a team's best runner, its most selfless blocker and its most flexible spare part. It has never once described where the man actually stands. More guides to the American game are collected on our United States hub.