Championship X factors: defense

The offenses usually command the spotlight, but with a pair of aggressive, explosive attacks on the field, the College Football Playoff National Championship presented by AT&T may well come down to which unit is slowed down first.

That will put the defenders under the microscope, and it may be up to a few overlooked contributors to help determine the outcome and decide the title. With kickoff quickly approaching for No. 2 Oregon and No. 4 Ohio State, ESPN.com reporters Chantel Jennings and Austin Ward look at a couple of potential difference-makers for Monday night's huge showdown.

Oregon CB Troy Hill: The redshirt senior was tasked with containing Florida State wide receiver Rashad Greene in the Rose Bowl Game presented by Northwestern Mutual, and he did just that. Greene tallied just 59 yards on six catches and didn’t reach the end zone once. Chances are that Hill will play a similar role against Ohio State. Only this time he’ll be shadowing Devin Smith, who has 11 receptions of 40 or more yards so far this season. Smith has been the guy that each quarterback -- yes first Braxton Miller, then J.T. Barrett, then Cardale Jones -- has looked for deep, and if that’s not enough, then consider that he has 12 touchdowns on 32 receptions this season. So he might not touch the ball a lot, but when he does, he’s very, very dangerous. Hill’s job will be containing Smith and limiting his yards after the catch when Smith does get the ball (because he will get it). -- Jennings

Ohio State safety Vonn Bell: The delay in getting the athletic playmaker into the lineup a year ago seems almost unthinkable now that the sophomore is rapidly developing into one of the most talented defensive backs in the nation. All that really matters for the Buckeyes is that Bell is on the field now. There is no question the most improved unit on the Ohio State roster is the secondary, and Bell’s nose for the football, his speed and his willingness to come up and deliver a hit on a ball carrier is a significant part of that development. He typically doesn’t receive as much acclaim as the standouts on the defensive line, led by Joey Bosa and his pass-rushing skills. The rapid rise of Darron Lee at linebacker has also drawn some attention away from the steady work Bell has been doing -- he had six interceptions this season for a team that led the Big Ten in picks. But make no mistake: If the Buckeyes are going to disrupt Oregon quarterback Marcus Mariota and create some turnovers, Bell figures to be right in the middle of that effort. -- Ward