As the NFL turns more to running back committees to stave off the effects of player overuse, specialization is key. Bell-cow backs that carry the ball 350 times a season are generally a thing of the past – in fact, only six NFL backs totaled 300 or more carries last season. Now, teams want a thunder-and-lightning combo featuring a power back inside, and a speedy threat outside and downfield.
This year, the two most impressive running backs line up on either side of that formula. While each player has the hypothetical talent to be the heart of an offense, they're more likely to be used in a rotation, with their teams playing to their best and most productive qualities. Clemson's C.J. Spiller is as exciting a playmaker as we've seen in recent years, and Ryan Mathews of Fresno State is coming up from under the radar with his own elite production:
C.J. Spiller, Clemson
Ryan Mathews, Fresno State
Pros: Spiller has amazing speed in just about every way: straight-line middle and deep, lateral agility, and stop-and-start in short spaces. Excellent vision and quick decision-making when bouncing outside – he can make multiple cuts and still maintain his quickness. He's very fast inside when asked to cut through a gap and go. A willing, though unexceptional blocker (his size factors in here), he's great in situations where he chips a pass rusher and takes a short screen. Can attack downfield as a receiver as well by taking a simple wheel or stick route and breaking past defenders for big plays. Will sometimes line up in the slot or outside. With his starting speed and outside vision, he's a devastating runner on draw plays. Has the ability to make a Percy Harvin(notes)-like impact as a return man in the NFL. Stronger than his size would suggest – he's not afraid to drop a shoulder and fight for the next break and he never missed a game at Clemson.
Pros: Mathews is faster than he looks, and has excellent straight-line speed for his size – this really shows up when he's in the open field and outrunning defensive backs. A great downhill runner who will wait for gaps and blast through, but he also has no problem blowing through obstructions. From the line to the third level, he will always make it difficult for his tacklers. Has excellent balance, which allows him to get through first contact and continue a run. One of the best backs in recent years fighting through second-level trash, and defensive backs will not enjoy trying to bring him down. Quick and decisive when one-cutting across slide protection. Keeps his shoulders square and his power forward even as he's turning or making cuts. Good stiff-arm and high-step, and he'll use both to extend his runs. Excellent red zone and goal-line runner.
Cons: Spiller wouldn't be able to hold up in the NFL at a 300-carry pace (at least, it wouldn't be advisable), but his sheer talent will have a team taking him somewhere in the top 15 and paying elite starter money. Not an elite tackle-breaker, but he doesn't have to be with his ability to blow by people. Will sometimes dance his way into a "stuff" at the line. Best in a scenario with a creative coaching staff that will use him in many different ways.
Cons: Mathews has medium burst when breaking runs outside, though his dash speed probably has us overestimating the need for this. Slightly worrisome injury history (missed seven full games during his time with the Bulldogs). Not an experienced receiver or pass blocker, but has potential in both areas. He'll need to upgrade those aspects of his game to be a true three-down back in the NFL unless the scheme allows for it.
Conclusion: If your team needs a speed threat out of the backfield, a killer receiver who can embarrass safeties with his speed, and a returner who can scare the life out of opposing special teams units, Spiller could be the ultimate 3-for-1 bargain. He fought through foot injuries in 2009 and still averaged 191 all-purpose yards per game. That included four kickoff returns for touchdowns, part of his NCAA career record of seven. He was the only player in college football to score a touchdown in every game last season, and he might be a fringe second-rounder for his receiving ability alone. The obvious comparison is Reggie Bush(notes), but Spiller transcends it. He's a jack-of-all-trades, master of most. A rare player.
Conclusion: Mathews led the NCAA in rushing yards per game (150.7) in '09, but don't assume that he made his bones against weaker WAC competition. He ran for 173 yards against Illinois, 145 against Cincinnati, 107 against Wisconsin, and 234 against Boise State. Above all, this is a guy who hates to lose yardage – he lost only 42 yards on his 276 carries in '09. Because he doesn't have elite outside speed, Mathews might be a best fit for a team with a hybrid blocking scheme featuring pulling guards, or as the thunder to someone else's lightning in a true zone system. In an era of committee backfields, Mathews can be a workhorse, though the team drafting him would be wise to consider his injury history and recent workload trends among NFL running backs.
Doug Farrar is a regular contributor to Yahoo! Sports' Shutdown Corner