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Air Raid Playbook: Examining basic defensive coverages

In the first installment of our series deconstructing the Air Raid offense Mike Leach brought to WSU, we take a look at the first thing a quarterback does when he comes to the line of scrimmage: Read the defense.

A QB must be able to read the defense and adjust accordingly.
A QB must be able to read the defense and adjust accordingly.

Throughout the next couple months leading up to the Crimson and Gray game, we will be presenting an Air Raid playbook series. The hope is that you'll get a better understanding of how the offense works and why it's conceptually able to exploit defenses, and if you're able to apply that to enhance your enjoyment of watching the Cougs, all the better.

In order to best understand the concepts involved and why they are effective, we need to first familiarize ourselves with a few basic defensive secondary coverages.

A defense can, and often will do a lot to disguise coverage. It is a cat and mouse game between offensive coordinator and defensive coordinator that can go unnoticed by the casual observer. Offenses have the advantage in knowing where their routes will be ran. Defenses counter by masking who will be responsible for covering those routes, making it more difficult for a quarterback to determine who is open and for an offensive coordinator to call a play with a distinct matchup advantage.

When used, different zone blitz packages and clever disguise tactics can make it very difficult to determine coverage after the snap, let alone before it. But a defense can't hide everything all the time. Defensive alignment before a play can tell a lot about the potential coverage an offense will be facing.

The Pre-Snap Read

A quarterback begins his Pre-Snap Read (PSR) of the defense as the offense approaches the line of scrimmage. This process becomes as automatic as buckling your seatbelt and checking your mirrors before you pull out of a parking space. First, a glance left to right over the entire field, not particularly focusing on one thing or another, this is called the "Soft Gaze" (Chris Brown).

Corner depth will tell you a lot about coverage and is the first check during the Soft Gaze. Five yards and in likely indicate Man or Cover 2. Seven yards off or more could be Cover 4 or Cover 3. Next, a quarterback notes the number of safeties and their location. And finally he will count the "front", comprising of the defensive line and linebackers.

One way defensive coordinators such as Monte Kiffin try to disrupt the offense is to disguise coverages pre-snap. (Photo: Kirby Lee, USA TODAY Sports)

No one singular pre-snap observation will tell you much, but when several are combined you can begin to get a clear picture. Corners tight, with two safeties on their respective hashes and outside linebackers splitting the distance between your inside receiver and the end man on the line of scrimmage give a very strong indication the defense is in Cover 2.

By this time in the PSR, the quarterback has his play and the offense knows what its running. Now the quarterback shifts to a "Hard Gaze" (Chris Brown). A play is designed to attack certain parts of a zone defense or beat man coverage, with the Hard Gaze the quarterback identifies which defenders he needs to pay specific attention to, or "read" after the ball is snapped. The position of those defenders will determine where the ball is thrown.

Air Raid plays attack open space on the field, where the open space is exactly will depend on the coverage. Receivers are taught to identify coverage, just like the quarterback, and will adjust their routes according to the specific defense.

A zone defense is attacked at its zone boundaries. Placing a receiver at the top and bottom of a zone will force a vertical strain on the defense. Likewise, a horizontal strain can be forced by receivers on the inside and outside of a zone. Some plays, like Flood in the Air Raid place a triangular stress on a defense, where there is both a horizontal and vertical strain on zone defenders. By attacking a zone with multiple receivers, a defender must choose who to cover, a decision made even more difficult and the resulting open space much larger if the receivers are on the boundary of his coverage zone.

When we look at WSU Air Raid plays you will see a lot of routes that settle along the boundaries of intersecting zones. These are the weakest points of secondary coverage and will either create open space by forcing coverage, or be in the open space when a defender is forced elsewhere.

With that, let's take a look at some basic defensive secondary coverage.

The Coverages


Cover 2 is a defensive staple. It has strengths in its run stopping ability, pass rush, a variety of blitz packages, and defending short crossing routes. Cover 2 has three major weaknesses; along the sideline behind the corner and in front of the safety, in the middle of the field behind the Mike linebacker, and when it tries to defend more than two receivers on vertical routes.


Cover 4 divides the field into quarters, each covered by its respective corner or safety, allowing it to defend multiple vertical threats. This is at the expense of the interior zones. Cover 4 is susceptible to short crossing routes that place a horizontal strain on the zone in the flat, hook to curl combinations that work the outside backers, and deep out or dig route combinations that place a vertical strain on a quarter zone.


Cover 3 rolls a safety (SS) up to cover the flat. This strengthens run the run stopping ability when compared to Cover 4, but the weaknesses are similar. Cover 3 can also be exploited by manipulating the free safety with vertical routes.


Quarter Quarter Half shows one side of the field in Cover 2 and the other in Cover 4. Defenses have also been known to combine Man and zone coverage in a similar fashion. This is typically used when an offense is stronger (either vertically or in the flat) to one side of the field vs the other, or when one side has more receivers than the other.



Very rarely do teams play straight man coverage away from the goaline. More often what you see is a brand of Cover 1 with at least one free safety. Nickel - 5 defensive backs (coverage back usually substituted for a linebacker) , and Dime - 6 defensive backs (either two linebackers, or a linebacker and a defensive lineman substituted), allow for man coverage with 2 free safeties, or man coverage within a zone defense, essentially playing "man and a half" on one wide receiver. Man coverage is highly susceptible to any crossing routes and is very weak against the run.

Now that you're a little familiar with some basic defensive coverages, stay tuned over the next couple months to see how WSU's Air Raid exploits them and get some things to look for in the spring game on April 20th.