The portion of a football team primarily responsible for keeping the opposing team from scoring points. The defense is made up of a combination of defensive linemen, linebackers, and defensive backs. The eleven players on the field will pursue the player with the ball in an attempt to tackle them as soon as possible and keep them from gaining yardage. Defensive effectiveness is measured by the amount of yards and points allowed during a game.
Defense can take on many different strategies with one primary goal: get the ball back to their offense as fast as possible. Usually, this is accomplished by stopping the offense on three consecutive plays, forcing the opposing team to punt. Sometimes, the defense can force a fumble or intercept the ball, getting the ball back immediately. The specific players on defense change depending on the alignment that the coach thinks will maximize the defensive's effectiveness on that play, sometimes substituting larger players to shore up the front line of the defense, and sometimes substituting defensive backs to guard against passing plays.