Most important player: UCLA Bruins

All players are equal, but some players are more equal than others. That's the basis of our Most Important Player series.

First off, quarterbacks are excluded to make things more interesting. It goes without saying, for example, that Oregon's Marcus Mariota is the Ducks' most important player.

And most important doesn't necessarily have to be "best." An All-American's backup can be pretty darn good, too.

Our most important guys are players who could swing a win total one way or the other, based on their living up to expectations. Or their absence.

UCLA: LB Anthony Barr

2012 production: Posted 83 tackles, 13.5 sacks and 21.5 tackles for a loss. He also forced four fumbles, blocked a kick and notched a safety.

Why Barr is so important: Another difficult choice. I considered defensive lineman Cassius Marsh -- a fiery player who steps in for Datone Jones as the leader of the defensive front. If he can continue to build on last year's fantastic production (50 tackles, eight sacks, 10.5 TFL) life will be easier for Barr. When his aggression is controlled -- and there have been reports that he's been a stronger leader this spring -- the Bruins will feed off of him.

Also, whoever wins the running back job will certainly be of great importance because they'll take pressure off of quarterback Brett Hundley. But with that position battle still undecided -- and the fact that it looks more and more likely that it will be by-committee -- the most logical choice is Barr.

Simply put, Barr is a game-changer. And he's expected to be even better than he was last year -- which is a frightening prospect when you consider what he was able to do with all of a six weeks of practice as a defensive player.

The numbers speak for themselves, and any discussions about the league's defensive player of the year in 2013 have to include the projected top-10 pick in next year's NFL draft.

We all know Barr's backstory, that he was a running back/fullback before Jim Mora and Co. came in and installed the 3-4 defense, converting Barr to an outside linebacker. After being injured last spring, he didn't actually start working at the position until fall camp. And then he blew up -- so much so that Mel Kiper has him as the No. 5 player on his 2014 draft boardInsider.

The Bruins face a tougher schedule in 2013, which includes trips to Nebraska, Stanford, Oregon and USC. They are also looking for leaders to fill the role of the departed running back Johnathan Franklin and the aforementioned Jones, among others.

Now that Barr has had a healthy offseason to work as a linebacker, he's added lean muscle to his frame and whatever remnants of being an offensive player that might have lingered are history. He spent most of this spring getting better in pass coverage -- which will make him a more diverse and well-rounded prospect, but it will also take some of the pressure off the Bruins defensive backfield as they rebuild the secondary.

Barr is on the verge of becoming a complete player -- a guy who can detonate quarterbacks and running backs in the backfield and make plays in pass defense. Those kind of elite defenders are rare. And Barr is that kind of elite defender.