In fact, the defense has three goals:
1. Keep the offense from scoring;
2. Gain possession of the ball (i.e., take the ball from the offense); and
3. Score. That’s right; the defense can score points. I will leave that for a later discussion.Even though it doesn’t know what plays the offense will run (although it may have suspicions based on the situation and which offensive players are of the field), the defense still has its own plays that govern what its players will do.
As with my post on the offensive line and quarterback, I will first focus on those players that begin each play at, or just behind, their side of the line of scrimmage (LOS): the defensive linemen and the linebackers. I describe these positions in the context of a basic defensive formation, called the 4-3 defense, to illustrate how these players are used on the field. Coaches use the 4-3 defense because it gives the players flexibility to adjust their positions based on the offense’s formation. Both runs and passes are well covered, so it is up to the players to match their speed and strength with the offense.
Position: Before the snap of the football and the start of the play, the defensive linemen (DLs) are positioned facing the offensive linemen on the opposite side of the line of scrimmage. The DLs are typically squatting in a three- or four-point “stance,” with both feet and either one or both hands on the ground. If there are three or five defensive linemen in a play, the nose tackle will line up across from the center; next to him are the left and right tackles; and on the other side of the tackles are the left and right defensive ends (or just “ends”). In the 4-3 defense, however, there is no nose tackle; only the tackles and ends.
Responsibilities: In general, the responsibilities of the DLs are: (1) to rush, or put pressure on, the quarterback, disrupting his ability to execute the play; and (2) stop running plays, by tackling the runner as close to the LOS as possible (or, better yet, behind it for a loss of yards).
Position: The linebackers (LBs) are positioned behind the DLs, within five yards of the LOS. In the 4-3 defense, there are three linebackers: right, middle and left. So, can you see why it’s called the 4-3? There are four defensive linemen and three linebackers. The remaining four players on the field make up the secondary and their roles will be described in a future post. Linebackers are typically in a “two-point” stance; that is, with no hands on the ground.
Responsibilities: The LBs have the same responsibilities as the DLs: to pressure the quarterback and defend running plays. However, because the 4-3 allows the defensive linemen to carry out these functions as well, LBs are also able to drop back further from the LOS and try to disrupt passes from the quarterback to his receivers.
The defensive players are not subject to the false start penalty like offensive players. The purpose of the false start penalty is to prevent the offense from moving in a way that makes the defense believe that the play has started. This would cause the defense to move forward across the LOS, committing one of a variety of penalties themselves. Since the defense has no prohibition on moving before the snap as long as it stays on its side of the LOS, you will often see one or more LBs and DLs shifting positions and stepping up to and back from the LOS. This is either because they are making adjustments based on the offense’s formation, trying to make the OLs flinch and commit a false start penalty, or just trying to intimidate the quarterback and the rest of the offense.
When the play starts, the DLs, and those LBs who are rushing the QB on that play, will advance toward the line of scrimmage. When a defensive player makes contact with an offensive lineman or other player, they try to break past that player to pursue the quarterback or the runner (the player with the ball). There are three legal ways to do this: (1) use brute force to push the offensive player back from the LOS; (2) jam the offensive player and try to go around him, usually with a spin move; or (3) use a “swim” technique to ward off the player’s hands and push through the line of humanity in front of him.
Though most people are watching on the quarterback and the ball when a play is going on, try every once in a while to focus on the battle going on in the “trenches” between the offensive and defensive lines. This is truly where the majority of physical struggle is taking place and you’ll wonder why they willingly get up and do it all over again just a few seconds later.