Felix Jones has rushed for 951 yards in his career, 284 of them on six carries.

Jones had 56, 49, 46, and 40 yard runs last year. He had 60 and 33 yard runs in 2008. Those six runs account for 29.8 percent of his career yardage. Take those runs away, and Jones averages 4.8 yards per carry for his career: very good, but not the eye-popping 6.5 yards per carry he currently averages.

When analyzing a running back, I like to look at the "shape" of his production. Is he a boom-or-bust back? How much of his production came on a handful of long runs? Is he the kind of back who will have a 12-carry, 16-yard game if he doesn't manage to rip off a 46-yard run?

I'm especially skeptical of guys with low carry totals and high per-carry averages. It all goes back to Troy Hambrick. Hambrick rushed for 579 yards and a 5.1 yard-per-carry average for the 2001 Cowboys, fooling some people into thinking he was a worthy heir to Emmitt Smith. Hambrick's long runs that year were 80 and 47 yards, accounting for 22 percent of his production. He was a very ordinary power back who surprised defenders on a few long runs, not a star in the making. Hambrick eventually became a featured back, but his 275-972-3.5-5 statline was both disappointing and misleading: one late-season 189 yard game salvaged a miserable year. He disappeared soon after that season.

Jones doesn't appear to be a Hambrick: even without his longest runs, he's very productive on a per-carry basis. (He's also a versatile receiver and return man, not a one-trick interior runner like Hambrick). Now all he needs is an expanded role in the offense. Jerry Jones keeps alternating between Jones and Marion Barber, championing a different one as his starter every few days. That's his prerogative as Caesar. At any rate, if Felix Jones does earn a 20-touch role, he'll be productive, with or without the occasional 60-yard lightning strike.

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Pierre Thomas is another running back with a high per-carry average but an uncertain offensive role. But Thomas averaged 5.4 yards per carry without the benefit of long runs: his longest gains were just 30 and 34 yards. Thomas was very consistent, with 71 of his 147 carries netting between three and nine yards and just nine stuffs for losses. Thomas should get more carries with Mike Bell gone, but you never know with the Saints: Reggie Bush could get more opportunities, someone else might emerge, or the Saints might just throw more often. It's good to know that Thomas can grind out 70 or 80 yards, five yards at a time, if he gets 15 carries – he doesn't need a long run to produce yardage.

When talking about big gains, it's hard to ignore Chris Johnson, the league's ultimate breakaway back. Johnson had runs of 91, 89, and 85 yards last year, plus a 57-yarder, a 52-yarder, and a smattering of 30+ and 40+ yarders. He totaled 693 yards on his 14 carries of over 30 yards. To put that in perspective, he would have finished 15th in the AFC in rushing based solely on those 14 carries, ahead of guys like Ronnie Brown and Willis McGahee.

Take away Johnson's top 14 runs, and his 352-1313-3.7 statline looks much more mortal, though still quite good. Even without his highlight-reel runs, Johnson can be a productive 1,000-yard back, which is good news to those of us who will be taking him first or second in a fantasy draft. Of course, Johnson's long runs won't go away this year, but it's unlikely that he'll have three 80+ yarders, either. Cut his big-play yardage in half, and you still have a tremendous player.

The player with the most Hambrick-like profile entering 2010 is Jerome Harrison, who gained 99 of his 862 yards in two carries against the terrible Chiefs defense. Harrison has a career resume filled with brief highlights and long stretches on the bench. Even without Montario Hardestry around to eat at his carries, Harrison looks like the kind of back who can kill you with one-yard runs and long doghouse sessions while you wait for that 71-yard touchdown. Harrison outgained both Thomas and Felix Jones last year, but given the choice, I would draft him third of the trio.

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Finally, there's a Reverse Hambrick at the bottom of the radar screen: Jerious Norwood. Norwood had a miserable year last year, battling hip injuries and looking sluggish when pressed into service. His 76-252-3.3-0 statline is an example of what happens when a boom-or-bust back doesn't go boom: his longest run netted just 21 yards. In 2008, he produced 95-489-5.1-4, but 26 percent of his yardage came on runs of 40, 44, and 45 yards.

Norwood is a reminder of just how volatile a boom-or-bust back's production can be, and the dangers of projecting a limited-carry player into a larger role. Norwood could bounce back to the 500-yard level this year — though the hip injuries have already returned — but he has lost that star-in-the-making luster. All told, it's best to take away a guy's highlight-reel runs and look at what he does on more ordinary plays so you don't run the risk of overrating him. That big-play back could be another Norwood, or another Hambrick.

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