Prevent defense, an umbrella term I am using here, is based on the idea that if you sit back and play soft coverage with the clock winding down an opposing offense will not be able to pick up enough yards to threaten you. Maybe you just can’t give up a touchdown, or all you have to do is keep a team out of field goal range.
Either way, the defensive coordinator drops into some sort of cover four or deeper variations of your base zone defenses with corners play 8-15 yards off the ball based on your needs and safeties sitting deep away from the line of scrimmage while you rush three.