The Notre Dame Fighting Irish proved last season that an elite defensive line can carry a team all the way to the national title game.
With eight starters on defense returning for Notre Dame, including most of its defensive line, the Fighting Irish will be poised to once again have one of the nation's top units.
South Carolina, led by superstar defensive end Jadeveon Clowney, will also have a terrific front line on the defensive side of the ball.
Ultimately, the defensive line sets the entire tone for a defense. If they can get good penetration, then offenses will have trouble moving the ball all game. But if they get dominated, then the linebackers and secondary are left to pick up the slack.
With the 2013 season just a few months away, here are the country's top 10 defensive lines: