Few workhorses come without risk

Ninety-nine percent of you are going to pick a RB in the first round. If you have the first pick, you're not going to go off the board and pick Peyton Manning or Drew Brees (unless you live in Indianapolis or New Orleans; I've seen that happen.) What you can't do is draft a risky RB1 or even RB2 unless you're getting tremendous value. When Clinton Portis and ShaunAlexander ruled the roost in the mid-2000s, picking them in the years they ended up injured would crush you. Last year, the top picks were more stable, but if you picked Ronnie Brown or Steve Slaton as a high-draft RB2, you suffered. Even workload warnings on guys such as Michael Turner and Adrian Peterson were ignored, and while they were productive, there's a big difference between taking Turner at the 1-1 slot, as many did, and taking him later in the first or second round. Peterson? He was still awesome, but not quite as awesome as he was in 2008. Adding injuries into equations involving risk, talent, consistency, and the rest that goes into setting up a draft board is tough work when it comes to RBs, but if you don't do it, you're going to lose.

There's not a lot of difference between 358 carries and the magic number of 370. Add in last season's 50 receptions and you might think that Johnson is in the danger zone.

He's not, though he's riskier than most think. Johnson's runs and passes aren't the punishing type we're used to seeing from backs that get 370-plus carries. He's elusive and crazy fast, plus he's not used too much on the inside runs that get the big highlight-level hits. What he's not is big, and in the car-crash physics of the NFL, the Ferrari loses to the Ford Explorer in a collision.

The key to Johnson's health is to keep successfully avoiding hits, which is partially on him and partially on the play-calling. According to stats from Football Outsiders, Johnson ran outside the tackles significantly more than other running backs (33.5 percent for Johnson vs. 21.1 percent for all other backs.)

One other wild card here is the presence of Vince Young. Young is an accomplished runner and has about 40 pounds on Johnson. While the Titans aren't going to start running the option, using Young's legs might be one way to make sure that Johnson's stay fresh. My one major worry is that Johnson's frame could be overtaxed without a solid backup. At the No. 1 overall in most mocks, I'm not sure Johnson is the stone-cold, no-brain lock that most are projecting.

Rice is a tough, solid back with a low center of gravity. (I'm still getting over that one play in which Rice made a catch, got hit so hard I thought he was going to get cut in half, and then bounced off it for the TD.)

Indeed, the difference between Rice and Johnson isn't a few more receptions, but their physical form. Rice is three (and probably four) inches shorter than Johnson and runs in a much more compact style. If that huge hit didn't show you that he had great balance, nothing will. Rice is, for all intents and purposes, a clone of Maurice Jones-Drew. Same size, same speed (4.39 for Jones-Drew at his Combine, 4.44 for Rice), same strength, same leg drive ... so why isn't Rice getting the same fantasy respect that Jones-Drew gets? Oh, he is? Jones-Drew is currently at No. 3 on MockDraftCentral's ADP report, with Rice just behind him. You can't really go wrong with either, but when you consider their respective offenses and Rice's superior receiving talents, I don't get why Jones-Drew is ahead. Neither is a significant injury risk either.

Glen Coffee walked away and Brian Westbrook was brought in. It's an important slot in the 49ers offense because too often, Gore has been out and that RB2 has needed to step up. Gore has avoided the serious injuries that could have really held him back, but the idea that he's going to go a 16-game season any time soon is wishcasting. Gore succeeded last year despite a terrible QB situation and a line that ranked near the bottom in every advanced metric. That says a lot about Gore, but he can only do so much on his own. Gore is likely to put up 1,000 yards and 10 TDs again this season, but are those numbers and the associated risk worth picking him over Michael Turner, Rashard Mendenhall, or even Ryan Matthews, who has a better offense and is projected to put up very similar numbers? I just can't do it. Gore's a nice late RB1 and a nicer RB2, but if you're picking your team based on thinking "this is the year my guy does something he's never done" you'll end up saying "wait till next year" sooner than you think.

As I detailed a couple weeks ago, Jackson is coming back from surgery on his lower back. Due to his running style, that part of his back gets taxed with every hit. If he stays with his style of "running behind his pads," he'll have to hope the surgeon's work holds up. If he runs more upright, he'll expose himself to bigger hits, especially to his legs. Any stylistic change is often one fraught with danger in the short term. If a player has to "think about things," he's not reacting normally.

(You can see this in something like Tim Tebow's throwing mechanics. When he was pressured, he went back to that long windup. It takes a while to make any change feel natural, to make it a habit.)

Watching Jackson run in pre-season isn't going to give us a perfect idea of how he'll hold up, but it will give us clues as to how, if at all, the back is affecting him. If he's looking anything close to 100 percent, he's worth a high pick just for the usage he'll get taking pressure off Sam Bradford.

If Bush is a bust, then he's a bust with a Super Bowl ring. You can't say he held the team back with his selection. It's more that Bush came in with outsized expectations.

He's had some injury problems along the way and his speed wasn't quite the gamebreaking kind it was supposed to be. He simply couldn't outrun people, Tecmo-style. While he learned to avoid them in other ways, though, he got beat up. And before the '09 season his knee needed microfracture surgery, although he came back well enough to help the team.

With a year between him and the surgery, plus a full off-season spent on football rather than rehab, if Bush is ever going to reach those outsized expectations, this is the year. He knows the offense, has enough distracting options around him to keep the defense from spying him, and has Pierre Thomas to soak up some of those inside runs. (Funny thing here -- Thomas is barely bigger than Bush, but the 3-4-5 guys on the depth chart in New Orleans are much bigger, so factor that in on Thomas' expectations.)

Bush hasn't proven he can stay healthy, but aside from his rookie season, this is the healthiest Bush has been coming into a season. With projections very low on Bush, he could end up being a real value pick at RB2.

I couldn't list all three backs up there, but with injuries to Fred Jackson and Marshawn Lynch, everyone seems to be looking to C.J. Spiller, the rookie phenom, as a big-time fantasy option.

Let me remind you of a few facts:

1. First, it's the Buffalo offense. I'm not sure anyone's a great option here.

2. If all three are healthy, only Lynch has shown he can take a feature load and he seems to be on the outs with the new coaching staff even before the injuries get factored in.

3. Jackson, last year's RB1 on a bad Bills team, is dealing with a broken hand. It should be cleared up enough to play by Week 1, though the offense probably won't ask him to go into the middle too often and could hurt him in the receiving game.

This is where Spiller comes in. He has explosive speed, but not Chris Johnson-level speed; he ran a 4.37 at the Combine, where Johnson was a 4.24 a year previous. Spiller's long injury history contrasts with Johnson as well. Really, Spiller is Reggie Bush -- similar speed, body and injury history, but with less experience and a terrible offense around him.

That leaves us with Lynch, whose ankle injury is keeping him buried at RB3 and the Bills' doghouse. He's the most likely short-yardage guy, though last year the Bills used Jackson more. It's a different staff, so who'll get the red zone carries remains to be seen. All that to get to this: stay away from Bills backs. They're all too risky.

Brown is currently No. 48 on the ADP chart at MockDraftCentral. That's high for a guy coming off a fractured foot, but low for a guy like Brown, who has proven he can come back from injury and return to level. The foot injury that ended Brown's 2009 season is one that several NFL players have come back from without significant issues, and there's no reason to believe Brown will be any different.

While teams have had time to adjust to the Wildcat offense that Brown runs, the Dolphins have done a lot to improve their standard offense. That could mean less defenses stuffing the box. Brown may lose some carries in the platoon with Ricky Williams, but he should also be a bit fresher. Drafting Brown below some feature backs is one thing, but putting him behind lesser backs with similar injury histories, like Felix Jones and Jonathan Stewart doesn't make sense to me. If he stays at the current ADP, where he's a late RB2, that could end up a huge value.

OK, if you were surprised by Brett Favre's return, welcome back from underneath that rock. You might have noticed he was wearing Crocs coming off the plane. Word is that his ankle is still swollen from off-season surgery, which is not a good sign. We'll have to watch how he moves when he practices and how he moves in the pocket once he gets back in game action. Look at the Vikings schedule -- there are a lot of speed rushers coming and if Favre has lost a step, it could be a major issue ... Eli Manning's cut looked more like something Gorilla Monsoon would call than an NFL injury. Twelve stitches and some concussion testing later, Manning should be fine in the long term. Of course, it could all have been avoided with a properly-fitted helmet ... Ryan Grant is back at practice after a concussion. The Packers handled this one the right way, making sure the hit Grant said "just rung his bell" was treated with the proper care. The sea change in NFL head trauma management is slow, but steady ... A rejuvenated LaDanian Tomlinson could be a double-edged sword for those that have Shonn Greene as an RB1. His ADP of 15 is high if he's splitting carries, but it's also likely to keep him healthier ... Knowshon Moreno is making progress with his strained hamstring and should be ready for the start of the season without limits. Missing practice time is making many wonder if Moreno will get enough reps to be the back of choice in the "Wing-Tebow" set ... Percy Harvin is back at practice. His chronic migraine issues are impossible to read, making your acceptance of risk key in where or even if you pick him ... I'll cover Larry Fitzgerald's MCL sprain in more detail next week when we cover the receivers, but early reports are optimistic. If you're drafting now, draft as if he'll play in Week 1, but slot him back a couple spaces ... If you're high on Johnny Knox, note the issues that speed players have after even minor problems with their hamstrings before picking him ... A sleeper out of Hofstra? Kareem Huggins is the talk of Bucs camp and with Cadillac Williams' history, Huggins is someone to think about with a late pick.

Be sure to follow me on Twitter @injuryexpert for quick updates on the big NFL injuries. Come Week 1, that feed will help you avoid those traumatic zeroes.