A sack in football is when a defensive player tackles the quarterback behind the line of scrimmage before he can throw a forward pass, resulting in lost yardage for the offense. It is one of the most valuable plays a defense can make, because it wrecks a passing play and pushes the offense backward at the same time.
What has to happen for a sack
The core requirement is intent to pass. A sack is recorded when the quarterback is attempting to throw and is instead brought down behind the line of scrimmage, or when he is chased out of bounds behind that line under pressure. The line of scrimmage is the spot where the play began, so a tackle there or beyond it does not count; the quarterback must lose ground. Because the passer usually drops back a few yards after the snap, most sacks end with the offense several yards worse off than where it started.
Why a sack is so damaging
A sack hurts the offense twice. It burns a down with no gain, and it moves the ball the wrong way, turning a manageable situation like second-and-6 into second-and-12. That yardage swing pushes teams into long-distance downs where the defense can anticipate a pass. A sack can also flip field position and, when it happens deep in the offense’s territory, set up a punt or even a safety if the quarterback is caught in his own end zone.
How sacks are counted
The sack is an official statistic, credited to the defender who makes the tackle. When two players share the stop, the NFL awards each a half sack, so a box score can show totals like 1.5 or 2.5. Yards lost on the play are recorded against the offense, and a quarterback’s “sacks taken” is tracked as well. These numbers are widely used to judge both pass rushers and the offensive lines charged with stopping them.
Runs, scrambles, and what is not a sack
Not every tackle of the quarterback is a sack. If a quarterback keeps the ball on a designed run, or scrambles and is dropped as a runner rather than a passer, the play is scored as a rushing attempt with a loss, not a sack. The distinction turns on whether he was trying to pass. This is why a quarterback who tucks the ball and takes off can be tackled behind the line without a sack being charged, as long as officials judge that he had become a runner.
The strip-sack
The most punishing version is the strip-sack, where the defender not only tackles the passer but also knocks the ball loose before he is down. The result is a fumble, and either team can recover it. A strip-sack that the defense recovers is a sudden change of possession, often in prime scoring range, which is why pass rushers are coached to swipe at the ball as they finish the tackle.
Coverage sacks and the blitz
Not every sack comes from a defender simply beating his blocker. A “coverage sack” happens when the secondary blankets the receivers so well that the quarterback has no one to throw to; he holds the ball too long, and the rush eventually gets home. In that sense a sack can be a team effort, with tight coverage buying the extra second the pass rush needs. Defenses also manufacture pressure with the blitz, sending linebackers or defensive backs who would normally drop into coverage. A blitz can overwhelm the protection for a quick sack, but it is a gamble: if the quarterback beats it, receivers may be left open downfield.
Sacks and the offensive line
Preventing sacks is largely a battle up front. The offensive line, and especially the left tackle who guards a right-handed passer’s blind side, is judged heavily on how few sacks it allows. Quarterbacks share responsibility too: a passer with a quick release, good pocket awareness, and the sense to throw the ball away rather than take a loss will be sacked less often. When protection breaks down repeatedly, offenses adjust by keeping a running back or tight end in to block, or by calling quicker passes that get the ball out before the rush arrives.
Who gets the sacks
Sacks are overwhelmingly the work of the pass rush: defensive ends coming off the edge, interior defensive tackles pushing the pocket, and linebackers or defensive backs sent on a blitz. Blocking them is the job of the offensive line, especially the tackles who protect the quarterback’s blind side. To see how these units line up, read our breakdown of NFL positions. And because a sack so often forces a long down, it is closely tied to whether an offense can move the chains and pick up a first down on the next play.
Frequently asked questions
What counts as a sack?
A sack is credited when a defender tackles the quarterback behind the line of scrimmage as he attempts to pass, or when a passer is forced out of bounds behind the line under pressure.
Does tackling a running quarterback count as a sack?
Usually no. If the quarterback is a ball-carrier on a designed run or has scrambled past the line, the tackle is an ordinary stop. The sack applies to a passing attempt behind the line of scrimmage.
Can two players share a sack?
Yes. When two defenders combine to bring the quarterback down, each is often credited with half a sack in the official statistics.
What is a strip-sack?
A strip-sack is a sack in which the defender also knocks the ball loose, creating a fumble that either team can then recover.
Is a sack in the end zone a safety?
Yes. If the quarterback is sacked in his own end zone, the defense is awarded a safety worth two points.
