Quarterback sacks

In American football and Canadian football, a sack occurs when the quarterback (or another offensive player acting as a passer) is tackled behind the line of scrimmage before he can throw a forward pass, when the quarterback is tackled behind the line of scrimmage in the "pocket" and his intent is unclear, or when a passer runs out of bounds behind the line of scrimmage due to defensive pressure. This often occurs if the opposing team's defensive line, linebackers or defensive backs are able to apply pass pressure to quickly get past blocking players of the offensive team (the quarterback's protection), or if the quarterback is unable to find a back to hand the ball off to or an available eligible receiver (including wide receivers, running backs and tight ends) to catch the ball, allowing the defense a longer opportunity to tackle the quarterback. A quarterback that is pressured but avoids a sack can still be adversely affected by being forced to hurry.

In the National Football League (NFL), it is possible to record a sack for zero yards. The QB must pass the statistical line of scrimmage to avoid the sack. A sack is also credited when a defender causes the quarterback to fumble the ball at or behind the line of scrimmage; this is also known as a strip sack. If a passer is sacked in his own end zone, the result is a safety and the defending team is awarded two points, unless the football is fumbled and either recovered in the end zone by the defense for a touchdown or recovered by either team outside of the end zone.

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