A strategy used by a defensive unit in which they will have a player other than a member of the defensive line attempt to pressure the quarterback. Typically, this will result in a linebacker or defensive back attempting to find a gap in the offensive line and tackle the quarterback. Teams can choose to blitz one or more players during a play, and this usually results in five or more players attempting to reach the quarterback.
The blitz is a high risk, high reward play by the defense. Since the defense is bringing more players to pressure the quarterback, it increases the number of people that the offensive blockers have to account for and increases the chances of a sack or an errant pass. However, this also reduces the number of people in pass protection, so if the blitz is unsuccessful there is a higher likelihood of a completed pass. Players that are effective at blitzing can time the play well and find gaps in the offensive line and reach the quarterback.