To say that Seastrunk is explosive is an understatement. The former five-star recruit who made his way to Baylor via transfer from Oregon made up for lost time at the end of last year, rushing for 831 yards and six touchdowns in the final six games (138.5 yards per game). Simply put: Seastrunk's speed is a fantastic fit at Baylor, where the Bears spread teams out and allow Seastrunk to hit vertical creases. He hasn't been shy about stating that he's going to win the Heisman in 2013, though to do so, he'll have to lead Baylor to a replica of RG3's final season in Waco.
So much of what Sims does is overlooked because he's not as electric as some of the other backs on this list. What Sims excels at is maximizing every carry that he gets. He's the best in the league at turning a two-yard loss into a three-yard gain with a lean this way and a shift that way. For a high-usage back, he just doesn't have many negative carries, and his 112.6 rushing yards per game led the Big 12 a year ago. He lacks elite size or speed, but Sims has everything else: vision, patience, balance that makes for a special back.
Gray didn't take over the starting job until more than halfway through the season, but he started five of the last six games and projects as the starter in a crowded, and talented, Texas backfield. One of the top high school running backs ever to play — Gray set the national record in touchdowns scored, among his other gaudy stats — Gray came into Texas expecting to make an early impact, and he did, rushing for 701 yards and catching passes for another 151. But Gray (5-11 207) looked bigger and faster in the spring and could really be ready to take off. His ability to catch the ball out of the backfield — he actually had 1,244 yards and 16 touchdowns receiving in high school — could make him even more deadly.
Like Gray, Williams has displayed the ability to destroy defenses in a number of phases. Williams rushed for 905 yards last year at 5.7 yards per carry and scored 11 touchdowns. But he also pulled in another 29 passes for 301 yards, averaging 10.4 yards per catch. Williams has great size at around 215 pounds, but he also has the speed to hit it deep. Just ask Texas — Williams took a handoff, made a few people miss at the second left and raced 95 yards for a touchdown. Also like Gray, it's unclear whether he'll make a run at the 1,000-yard mark because Oklahoma should be pretty good at running back. But he's as good as they come.
5) Tony Pierson, Kansas
It was a tough pick here between Pierson and Kansas State's John Hubert. But I'll go with Pierson because of his superior explosion and all-around play. Pierson averaged more yards per carry (6.5 to 5.0) and actually had more rushing and receiving yards despite playing fewer games. One of the fastest players in the Big 12, Pierson figures to get the ball in a variety of ways again this year. He had six catches for 99 yards against TCU and actually looked poised to destroy that mark against Kansas State with six catches for 63 yards and a touchdown in a little more than a quarter's work before he got hurt. Add that to the 202 yards rushing he had at Texas Tech, and Pierson is a versatile and dynamic threat and a great pairing with Sims.