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Football Defensive Line

Defensive Line

The defensive line in football is a group of linemen on the defense:

Football Defensive Line

The defensive line is positioned on the line of scrimmage at the start of every down.

The defensive line is responsible for:

Nose Tackle

The nose tackle is a lineman in the middle of the defensive line. He stands opposite the center in the offensive line. The nose tackle charges the center player after the snap.

Football Nose Tackle
PRO TIP: The nose tackle must be careful not to enter the neutral zone before the snap. A penalty called encroachment will be called on the nose tackle.

Defensive Tackle

A defensive tackle is one of two linemen in the defensive line that stand opposite the guards of the offensive line:

Football Defensive Tackle

Football Left Tackle

The left tackle is the linemen on the left of the nose tackle in the defensive line.

IMPORTANT: There is also a left tackle position in the offensive line, but do not confuse the two.

Football Right Tackle

The right tackle is the linemen on the right of the nose tackle in the defensive line.

IMPORTANT: There is also a right tackle position in the offensive line, but do not confuse the two.

Football Defensive End

The defensive end stands both ends of the defensive line. They stand opposite the offensive tackles. Defensive ends have the best chance to sack the quarterback because they are close to the sidelines.

Football Defensive End

4-3 Defense

A 4-3 defense is a defense with four defensive linemen and three linebackers. A defensive line does not have to have five players on the line of scrimmage.

Football 4 3 Defense

3-4 Defense

A 3-4 defense is a defense with three defensive linemen and four linebackers. A defensive line does not have to have five players on the line of scrimmage.

Gaps and Alignments

Defensive coaches use a combination of lettering and numbering systems to describe specific "gaps" between the offensive linemen, as well as how defensive linemen will line up in relation to the offensive linemen across from them.


The A gaps are located in between the center and guards. The B gaps are between the guards and offensive tackles. The C gaps are between the offensive tackle(s) and tight end(s), and the D gap is outside the tight end.


For defensive line techniques, even numbers are for "head-up" positions (when the defender lines up directly across from the offensive lineman) starting at 0 across from the center and ascending order to the outside. Odd numbers are for alignments (or "shades") to the outside shoulder of the offensive player. There also inside-shoulder techniques, which use even numbers followed by an "i" designation (because the defender is lining up even with the offensive lineman's eye).

Gap and technique codes are used to quickly tell players where to line up and where to go when the play begins in a timely manner. For example, in a 4-3 Over defense, the strong-side defensive tackle lines up in a 3-technique and plugs the B-gap.