2012 numbers: Posted 83 tackles. He also had 21.5 tackles for a loss and 13.5 sacks -- both in the national top 15. He also broke up five passes, forced four fumbles, blocked a kick and notched a safety.
Why he could win: Notre Dame's Manti Te'o reminded people that yes, defensive players also are eligible for the Heisman. And Barr proved to be one of the most dangerous linebackers in the country in 2012. He's already viewed as a potential top-10 pick in the NFL draft, so the fact that he's coming back should allow him to refine his skills.
Standing in his way: He's a defensive player -- which means he will have to have out-of-this-world production to even get his foot in the door. Of all the Pac-12's returning defensive players, he probably stands the best chance.
2012 numbers: Rushed for 1,929 yards on 303 carries (6.4 average) and 23 touchdowns. He also caught 36 balls for 303 yards and a touchdown.
Why he could win: He comes in with a name -- having been the leading rusher in the nation last year. He's a big-play back who should continue to produce plenty of highlights. Some off-field issues are a distraction, but those figure to be settled by the time 2013 rolls around. With similar numbers, he'll be right up in the conversation.
Standing in his way: Arizona has to break in a new quarterback, and if the threat of the pass isn't there -- or the threat of a running quarterback -- Carey could see his numbers decline. Also, team success plays a role, so as Arizona goes, Carey's candidacy may go as well.
2012 numbers: He completed 318 of 478 passes (66.5 percent) with 29 touchdowns to 11 interceptions. He also ran for 355 yards (he netted 702, but was sacked 52 times, second worst in the league) and nine touchdowns.
Why he could win: He's one of several redshirt freshmen quarterbacks who showed they have the maturity and gumption to lead an offense. He's a phenomenal athlete who should have his team back in the Top 25 next year. He turned some heads in 2012.
Standing in his way: The fact that there is another explosive young quarterback in his league (see below) and another explosive young quarterback already has won the Heisman. He won't have Johnathan Franklin next year either to carry some of the load, so for as good as he was, he'll have to take a big step forward to stay relevant in the Heisman conversation. Some better pass protection coupled with him knowing when to throw it away should help, too.
2012 numbers: He completed 241 of 359 pass attempts (67.1 percent) for 3,039 yards with 29 touchdowns and 9 interceptions. He also rushed for 516 yards and a score. He ranked ninth nationally in passing efficiency.
Why he could win: If Kelly can lead his team to a 5-0 start, which would include wins over Wisconsin, Stanford, USC and Notre Dame, you can bet people are going to take notice. If he does it producing similar numbers to the 2012 season, he'll get the recognition that an efficient and talented quarterback deserves.
Standing in his way: The same schedule that could propel him as a contender could also knock him right out of the running. He's in a similar spot as Washington's Keith Price was last year. Lots of potential, but a brutal first half of the schedule seemed to set him back for the season. If Kelly can overcome the front end, expect him to be on the radar.
2012 numbers: Caught 118 balls for 1,721 yards and 14 touchdowns. He was second nationally in receptions per game, receiving yards per game and third in all-purpose yards.
Why he could win: He's the reigning Biletnikoff winner -- so he already returns as one of the best at his position. And the fact that he might be the most explosive and dynamic player in the country helps, too. There isn't much he can't do with a football in his hand.
Standing in his way: Like Arizona, the Trojans have to break in a new quarterback and they'll need to win more than seven games next year. Lee was associated with USC's epic slide and that cost him dearly, because on merit alone, he should have been the winner in 2012 -- or at least a finalist. Perhaps the expectations won't be so high at USC next year, so similar numbers will carry more weight.
2012 numbers: He completed 230 of 336 pass attempts (68.5 percent) for 2,677 yards with 32 touchdowns and 6 interceptions. He also carried 106 times for 752 yards and 5 touchdowns -- including a season-long 86-yarder. He finished seventh nationally in passing efficiency.
Why he could win: Oregon will be hanging around the top two for a while next year -- and if Mariota can improve on already stellar numbers, he'll get noticed. The fact that Chip Kelly returns is a big plus because Mariota's development and maturation won't be interrupted. He's a true dual threat with a team that will contend for the national title.
Standing in his way: That guy who won the Heisman will probably be at the top of a lot of lists going into next year. Mariota will have to impress to get moved above him in the pecking order. Also, much like USC last year, expectations will be high for the Ducks. Bad performances will be scrutinized harder than great ones.
2012 numbers: Carried 92 times for 701 yards and 11 touchdowns. He also had 45 catches for 445 yards and 5 scores. As a returner, he averaged 17.1 yards per punt return and returned one for a score and he averaged 24.3 yards per kickoff return including one for a touchdown.
Why he could win: Have you seen this guy run? He's arguably the most explosive player in college football and his reputation precedes him. He'll already be on a lot of watch lists. He's a highlight reel waiting to happen every time he touches the ball. The punt return against Colorado was, in a word, sick.
Standing in his way: He has to have more touches if he's going to make a serious run. Kelly will use him how he sees fit. And if that means sporadic touches throughout the game, so be it. I'm certainly not going to tell Chip Kelly how to run his offense. But if Thomas is going to be taken seriously as a Heisman contender, he needs the numbers.