Football Defensive Alignment Terms

By Howie Long and John Czarnecki from Football For Dummies, 4th US Edition

To better understand the inner workings of the defense in American football, you need to know how a defense lines up. Most defenses line up according to where the tight end on offense lines up. A defensive player, generally a linebacker, yells “left” or “right,” and the remaining players react and align themselves. Alignments are critical to a defense’s success. If the defense isn’t in the proper alignment, the players put themselves at a great disadvantage prior to the snap of the ball.

Here are some helpful explanations of terms used to describe defensive players and their alignments:

On or over a player: The defensive player is directly across from the offensive player and no more than a yard apart — virtually helmet to helmet.
Inside a player: The defensive player lines up with his right shoulder across from the offensive player’s right shoulder. The defensive player’s right shoulder can be directly across from the offensive player’s helmet.
Wide of a player: The defensive player is facing forward, and his entire upper body is outside the nearest shoulder of an offensive player. When the center snaps the ball, the defensive player wants a clear path forward so he can use his quickness to beat the offensive blocker off the line of scrimmage.
Over defense: In this defensive alignment, four members of the defensive team shift position in order to put themselves directly opposite each player aligned on the strong side (tight end side) of the offensive formation.
Under defense: Exactly the opposite of the over shift. This time, three defensive players line up directly across from the center, guard, and tackle on the weak side (non–tight end side) of the offensive formation, leaving only a defensive end opposite the offensive tackle on the strong side of the formation.

The open end side, or weak side, is opposite the tight end, where the split end lines up on offense. Most defenses design their schemes either to the tight end or to the open end side of the field. When linebackers and defensive linemen line up, they do so as a group. For example, they align over to the tight end or maybe under to the open end.