The 3-4, 4-3 and the 46 defense, all different formations focused on the same goal of stopping the opposition. With the pick of Quinton Coples many have hinted that the Jets will be making a switch from their familiar 3-4 formation, to the more popular and widely used 4-3. Sporting the fifth best total defense in 2011, a switch from their current philosophy may leave some scratching their heads.
The current 3-4 defensive alignment puts a strong emphasis on confusion and flexibility. With only three down lineman the defense can send an additional rusher from any part of the field, while still maintaining seven defenders in pass coverage. This is the key to the 3-4 defense as the opposing offensive line may not know who the fourth rusher is until the ball is snapped, possibly creating confusion and indecision which can result in a more effective pass rush.
The 4-3 defensive formation utilizes a four down lineman look which better occupies offensive lineman and can allow linebackers to roam the field in open space. With standard seven defender pass coverage the offensive line knows the four designated rushers will be the down lineman, making pass protection simpler, and assignments easier to recognize. This formation relies more heavily on having elite defensive lineman on the outside that can consistently beat one on one match ups to create pressure and get to the quarterback.