Chris Huston of CBS Sports previews the top Heisman Trophy candidates after USC’s Matt Barkley’s latest loss to Stanford:

Week 3 of the college football season is in the books, and the race for the 2012 Heisman Trophy has been dramatically altered.

USC’s Matt Barkley is the latest preseason favorite to stumble, throwing two interceptions in a huge loss to Stanford.

If you had told me before the year began that Barkley, Denard Robinson and Montee Ball would all be out of the Heisman race by the middle of September, I would’ve said you were crazy.

But it’s happened, and now it’s a wide-open competition. Any number of candidates could emerge. The next two weeks will give us a better understanding of the Heisman terrain, but for now the race is very fluid.

Keep in mind that the goal of this Heisman Watch is not just to track who is playing well from week to week. This is not a college football version of Kasey Casem’s top 40. The goal is to figure out who will ultimately win the trophy. We take a long view of the race, factoring in not only individual performance, but also schedule, team success and the historical voting trends of the Heisman electorate.

These are the players who currently stand the best chance of actually winning the Heisman Trophy. Keep in mind that some players not on this list will undoubtedly finish in the top 10 of the final Heisman voting. That’s all well and good, but this Watch does not exist to gauge their prospects.

1. Geno Smith, QB, West Virginia — Smith is off to a great start so far this season, with 734 passing yards and nine touchdown passes (with no interceptions) in his first two games. He is completing an amazing 88 percent of his passes and has an efficiency rating of 209. He is on pace to run and pass for 60 touchdowns. Granted, he is putting up these numbers against awful competition, but we all know he’s a very good quarterback playing in a passer-friendly system. It’s going to be difficult to for him to maintain this level against Big 12 competition, but he’ll still be very productive. As with Robert Griffin III last year, he’s not expected to lead his team to an undefeated season, and so Heisman voters will look to his overall numbers and how well he performs against Big 12 traditional powers like Texas and Oklahoma to gauge his worthiness. Given his solid name recognition, his potential for an elite statistical season and his odd status as a Mid-Atlantic player competing in the Southwest, he’s at the top of this Watch … for now.

2. Aaron Murray, QB, Georgia — Murray is not getting much Heisman buzz at the moment, but he is well set up to make a run for it in the season’s second half. He replaces Barkley as the candidate whose main selling point is that he is the quarterback for national title contending team (while AJ McCarron and Zach Mettenberger can also make this claim, neither will produce the numbers necessary to win the Heisman). He has done well so far, throwing for 842 yards and eight touchdowns in his first three games. He is on pace to have 3,653 yards and 35 touchdowns by the time the Heisman vote is due. Still, his fate is inextricably linked to the fate of his team, so it’s vital for UGA to keep winning. Georgia will be favored the rest of the way and if Murray can keep playing at this level while leading his team to an undefeated season, he’ll be knee deep in Heisman hoopla.

3. De’Anthony Thomas, RB, Oregon — Barkley’s collapse helps out Thomas, who becomes the Pac-12’s top candidate as a result. He is the race’s all-purpose candidate, and voters will focus on his overall yardage, his touchdown-to-touches ratio and his ability to crank out highlight-reel plays with regularity. Thomas is averaging 159 all-purpose yards per game, which is 17th nationally, but he’s only touched the ball 31 times in three games as Oregon has been blowing out lesser competition. He is also tied for fifth nationally with seven touchdowns. He’s on pace to have 2,100 all-purpose yards and score 30 touchdowns, which should be more than enough to challenge for the Heisman. Oregon’s schedule is favorable, and Thomas should have plenty of opportunities to build up his resume before taking on USC in a key matchup in early November.

4. Braxton Miller, QB, Ohio State — Miller passed his first test this past weekend, helping the Buckeyes survive a scare against Cal. In fact, Miller came through in the clutch, hitting Devin Smith for a 72-yard touchdown with 3:26 remaining to provide the margin of victory. Miller continued his impressive production, accounting for 324 yards of total offense and five touchdowns. His numbers through three games are very close to where Tim Tebow’s were after his first three games as a sophomore starter in Urban Meyer’s system and he’s doing it without the kind of dynamic vertical threats Tebow had at his disposal. He is on pace to have 2,436 passing yards and 1,500 rushing yards with 48 total touchdowns in just 12 games. Even without a conference title game to buoy his campaign, these numbers are good enough to win. Can he join Andre Ware as the only players to win the Heisman while on NCAA probation?

5. EJ Manuel, QB, Florida State — The Seminoles finally played a team from a BCS conference and didn’t miss a beat, crushing Wake Forest, 52-0. As usual, Manuel didn’t play a full game and his numbers, while efficient, weren’t overwhelming. On the season, he’s completing 71 percent of his passes for 525 yards with six touchdowns and one interception. If the ‘Noles are to remain undefeated, I fully expect he will be called upon to pick up the pace and so he’ll be able to put up the kind of statistics that would merit Heisman consideration. His position at No. 5 on this Watch will be justified if he leads FSU to a win over Clemson this coming Saturday. A loss to the Tigers will knock him off the list.

For Full List:

http://www.cbssports.com/collegefootball/blog/eye-on-college-football/20205571/week-3-heisman-watch-geno-smith-leads-wide-open-race-as-matt-barkley-falters