A quarterback sack occurs when a defensive player tackles the quarterback behind the line of scrimmage while the quarterback is attempting a forward pass. In common usage the term applies to plays in American football where the passer is taken down before he can throw. The action may be recorded as a sack even if the quarterback has moved from his original spot, provided the play began as a pass attempt rather than a designed run. See also quarterback for position context.
Key rules and how sacks are recorded
Different leagues and statisticians apply slightly different criteria when assigning sacks. The National Football League began officially recording sacks as an individual statistic in 1982, and its guidelines are widely referenced. When two defenders combine on the tackle, each is typically credited with a half-sack. Plays in which the quarterback is attempting to run are usually scored as a tackle for loss, not a sack. A sack that forces a fumble is often called a "strip-sack," and if the tackle occurs in the offense's own end zone it results in a safety.
Common pass-rush techniques
- Blitzes: sending extra defenders to overpower protection.
- Edge rushing: relying on speed and leverage around the tackle.
- Power moves: bull rushes, swim and rip moves to defeat blockers.
Sacks are both a tactical objective and a momentum-changing event. A well-timed sack can stall drives, increase distance on subsequent downs, create turnover opportunities, or result directly in points via a safety. Defenses design stunts, twists and coverage schemes to create mismatches and free rushers, while offenses counter with quick passing, slide protections and rollouts to keep the quarterback out of harm's way.
The term "sack" was popularized in the 20th century and is often associated with pass-rushing specialists. Individual season and career sack totals are prominent measures of defensive success; for example, New York Giants defensive end Michael Strahan set the single-season NFL record with 22.5 sacks in 2002. League record-keeping and historical comparisons can be complicated by differences in when and how statistics were tracked.
Sacks remain one of the most cited defensive statistics because they combine the skill of the rusher with direct impact on field position and game flow. Analysts and coaches study sack tendencies to evaluate pass-rush effectiveness, adjust protection schemes and plan game-day matchups.
For more background on rules and historical data consult official league resources and team histories, including the National Football League and individual franchise pages such as the New York Giants.