- Defensive line: (DL) consists of three to six players who line up immediately across from the offensive line. They try to tackle the running back if he has the ball before he can gain yardage or the quarterback before he can throw or pass the ball.
- Defensive backs: (DB) Either three or four players which are either cornerbacks or safeties. They cover the receivers and try to stop pass completions. They occasionally rush the quarterback.
- Linebackers: (LB) They line up between the defensive line and defensive backs and may either rush the quarterback or cover potential receivers. Linebackers also play a key part in stopping the running back.
Basic Formations:
3-4 (Shown above): Three defensive lineman, four linebackers, and four defensive backs. Most often seen in the NFL.
4-3: Four defensive lineman, three linebackers, and four defensive backs. Most often seen in College.
