Blitz (American football)
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In American football or Canadian football, a blitz, or quarterback rush, is a team defensive maneuver against an opponent's passing play in which the defense sends more players than the offense can block. Usually, blitzes are one or more linebackers or defensive backs, who normally remain behind the line of scrimmage during a play, but are instead sent across the line to the opponent’s side in order to try to tackle the quarterback or disrupt his pass drop. The name of the play is taken from the Blitzkrieg, a German strategy of the "Lightning War" during World War II.
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[edit] History
Don Ettinger, a defensive tackle for the New York Giants, invented the blitz during his brief NFL career (1948 – 1950). Larry Wilson, free safety for the St. Louis Cardinals from 1960 to 1972, pioneered and perfected the safety blitz, a play originally code-named "Wildcat." Defensive coordinator Chuck Drulis is widely credited with inventing the safety blitz.
[edit] How blitzing works
On passing plays, the offense always has at least 5 men blocking. From left to right, they are: left tackle, left guard, center, right guard, right tackle. Depending on the personnel, formation, and blocking principles the offense uses, they can have a maximum of 9 players blocking on any given pass play (this type of maximum protection is succinctly called "Max Protect"). Since the QB is throwing the pass, he cannot block and must have at least one receiver to catch the pass. Assuming the lone wide receiver is covered by a defensive back, this leaves the defense 10 players to rush the QB versus the offense's 9 blockers--the offense is outnumbered and at a disadvantage. Because the QB cannot block during passing plays, the defense always has one more man available to rush than the offense can block.
Usually offenses do not max protect often, varying the levels of protection available depending on the play design and the QB's pre-snap read of the defense. The more receivers the offense has running passing routes, the better their chances are of completing the pass. This factor allows defenses to devise and execute a staggering variety of blitz packages between any number of their coverage personnel, trading tight coverage of receivers for proactive aggressive disruption of the play.
By nature, blitzes are risky endeavors for the defense. Since the defense is taking away coverage defenders to rush the QB, there necessarily are holes in pass coverage. The defense does not and cannot cover all offensive players, but rather through the blitz, is proactively involved in rattling the QB, sacking the QB, disrupting QB timing, or forcing him to make an error such as an interception or fumble.
The most common blitzes are linebacker blitzes. Safety blitzes, when a safety (usually the strong safety) is sent, and corner blitzes, where a cornerback is sent, are less common. Sending a defensive back on a blitz is even more risky than a linebacker blitz, as it removes a primary pass defender from the coverage scheme, but is also less likely to be picked up by the offensive team’s blockers.
There is some confusion among average fans as to what constitutes a blitz. Blitz is colloquially used to describe any time a LB or DB crosses the line of scrimmage when in actuality, a blitz is defined as the defense rushing the QB with more men than the offense has accounted for and can block. For example, if the defense rushes 5 men, that does not constitute a blitz (as a minimum of 5 blockers are on the offensive line).
[edit] Defensive shells and techniques
Blitzes are usually run from "Cover 1" coverage shells which assign one man to guard the entire deep field, though blitzes can be employed in nearly any coverage scheme. Cover 1 is most effective because it allows a larger number of defensive players to tighten down on the line of scrimmage thus increasing the variety of blitzes possible.
Since the main goal is to disrupt the offensive play before it even develops, many blitz packages encourage cornerbacks to play tight man bump and run coverage to disrupt the wide receivers' release and prevent them from running their pre-assigned routes. The non-blitzing safety, usually the free safety, has an enormous amount of field to protect and is at a serious disadvantage if the blitz is unsuccessful and receivers threaten his coverage area. As such, he usually works for depth upon the snap of the ball, backpedaling into his assigned zone.
Linebackers are either blitzing or in pass coverage. Blitzing LBs can employ various stunts to confuse the offense's blockers and break down their protection scheme. Coverage LBs in a Cover 1 scheme will usually have man responsibility on a halfback, fullback, or tight end.
Some defensive schemes employ "key" blitzes where a player will blitz only if his assigned man stays in to block thus keying his action off the action of his man. If his man releases into a pass pattern, then the defensive player will cover him. For example, if weak side linebacker has the fullback as his man, if upon the snap of the ball the fullback blocks, the linebacker will blitz.
[edit] Advantages and disadvantages
Advantages gained by blitzing are obvious: proactively disrupt the offense's play before it develops and cause enough pressure on the quarterback to force him into a turnover.
Disadvantages abound in any blitz scheme as well. First, the offensive linemen are usually trained to recognize a blitzing player before the snap of the ball. They communicate with each other at the line of scrimmage using code words that shift the protection to the blitzing player's side thus strengthening their blocking front. The Quarterback can also call other players into the protection scheme with audibles if he feels that his current protection is weak. With good protection calls and fundamental blocking principles, some blitzes can be "picked up"--stopped at the point of attack.
Second, the tight man bump and run technique typical of blitz scheme cornerbacks can be defeated with aggressive WR release moves. Once this happens the CB is at a disadvantage and must regain ground and position quickly to prevent a catch. If the blitz is picked up, the WR can create enough separation to become open relatively quickly.
Third, if the blitz is picked up, the one deep defender (usually the free safety) has an enormous amount of territory to guard. If two players simultaneously threaten his zone, he must decide which one to cover. The QB can read his reaction and throw to the defender that he does not decide to cover, usually for a big gain.
Fourth, if the pass is caught, there are fewer defenders and larger gaps between defenders, meaning that the receiver can get more yards after catch and possibly turn a minimal gain into a dangerous play.
[edit] How to beat the blitz
Offenses employ the above procedures to beat the blitz as well as two other techniques and passing route combinations designed to exploit weaknesses in a blitzing scheme.
One of those techniques is called "throwing hot," which entails intentionally leaving one blitzing defensive player unblocked. The offensive line usually makes pre-snap adjustments so that the "free" rusher is clearly within the QB's field of vision. This limits devastating blind-side hits on the QB by rushers.
The other technique, sometimes used in conjunction with throwing hot, is called sight adjustment. Receivers are taught to run into the empty spot vacated by a blitzing player instead of running their pre-assigned pattern. The QB sees the free rusher or blitzing LB/CB and knows that the receiver will sight adjust accordingly and run a route that takes him into the hole left by the defender.
The West Coast Offense is an offense that focuses on ball control and short passes. This is a well timed offense where the quarterback throws the ball quickly to avoid the rush, but still allow the receiver to get behind the blitzing players.
