A screen pass can be effective, but it also can be risky because it is rather easy for a defensive player, even a lineman, to intercept this short pass if a defender gets in between the quarterback and the intended receiver. If the pass is intercepted, there are often few offensive players in front of the intercepting player, thus making it much easier for the intercepting team to earn a large return or to score a touchdown.
Screens come in all shapes and sizes. A screen to a running back to either the strong or short side of the field in the flats is often just called a screen. Screens to Wide Receivers come in four forms: The Bubble Screen, Middle Screen, Slot Screen and Slip Screen.
The bubble screen was essentially created by Joe Tiller, current coach of Purdue, when he was coach at Wyoming. The bubble screen involves a receiver taking a step forward, then darting toward the quarterback to receive the ball while the linemen release to clear a path for the receiver. The benefit of the bubble screen is it works against zone or man coverage, the downside is that it is timing, and a zone blitz or defensive end dropping into coverage messes up the timing, and this usually results in a sack.
The middle screen is like the bubble screen, except instead of being executed to one side of the field or another, the receiver continues his route to the middle of the field. The linemen release up the middle of the field in front of the receiver.
A screen pass is sometimes referred to as a shovel pass, which is also referred to as a shuttle or shuffle pass. Unlike a screen pass, which is a type of play, a shovel pass is actually a different throwing motion. To throw a shovel pass the quarterback palms the football, and "shovels" the pass directly forward to the receiver, usually with a backhand or underhand motion. When a designed play calls for the quarterback to use a shovel pass forward to a receiver it is, by definition, also a screen pass. Many times, however, the quarterback will be scrambling or about to be sacked and will shovel pass the ball to a receiver who was not the intended target of the called play. A shovel pass is useful in this situation because of its smaller range of motion and quick release. In this instance the shovel pass is not a screen pass.
If run properly, the defensive backs will be run out of the play by the receivers, and the defensive line will penetrate too far to stop the short pass from being thrown. The only defenders left will be linebackers, which will be picked up by the "screen" of offensive linemen in front of the receiver—hence the name "screen pass."
There are different types of screens that can be thrown, such as: