By Vinnie Iyer

updated 8:40 p.m. ET July 23, 2007

Friday, I blogged about what I thought were the seven shakiest quarterback situations in the NFL as training camps are set to open. Some of you noticed I didn't include the Giants (Eli Manning) or the Bears (Rex Grossman). I just don't think you can really qualify for "shakiest" when you have a playoff berth on your recent resume.

Moving on, it's time to examine which teams have the biggest concerns at running back. Really, when you take into account the proliferation of committee systems, the depth of all-around talent at the position, the rise of big blocking lines, the fall of dominant run defenses and decreasing pressure on teams to declare a "feature" back, most teams are in pretty good shape.

Two teams not on the shakiest list are the Chiefs and Cowboys. I'm expecting Kansas City to pay Larry Johnson what he wants at some point soon, and even though Dallas gets attention for having a cloudy running back situation, it could be a lot worse than choosing how to best use Marion Barber and Julius Jones together.

So below are the true shakiest seven backfields, in no particular order:

Titans. While the Broncos are loving the fact Tennessee let Travis Henry go, Vince Young is left as the most reliable runner in Nashville.

Rookie Chris Henry (no relation to Travis) is a speed back, but there are questions whether he's surehanded enough to handle an immediate all-around role. Second-year back LenDale White is a power back, but his injuries and attitude issues have held him back. And then there's Chris Brown, once released but re-signed in the wake of the developing situation with Henry and White. Brown has been explosive in stints, but his upright style makes him as a big a durability concern as White. Not one in the three is in position to win a No. 1 job outright -- this is headed for mix-and-match patchwork until one of the two younger backs emerges after camp.

Lions. The team didn't take any chances with the fragile state of Kevin Jones' Lisfranc fracture, giving up ace cornerback Dre' Bly in a trade to get former Broncos speedster Tatum Bell. It also got a power back in T.J. Duckett, who did nothing in Washington in his first year away from Atlanta.

It's unsure when Jones will be ready, and considering history of injuries, can he actually hold up when he returns? Jones did thrive under Mike Martz but so can Bell because he has the speed to take advantage of the gaps that will come about when teams play deep for Roy Williams and Calvin Johnson. Bell, however, never live up to his potential in Denver, so he's a bit of a wild card with his second chance.

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Raiders. Dominic Rhodes got the free-agent deal he wanted to leave Indianapolis, only to turn around and get suspended four games for violating the NFL's substance abuse policy. LaMont Jordan is coming off a torn MCL in his left knee that ended his second season with the Raiders last Nov. 19. Rookie Michael Bush probably is a year away as he's coming off a broken leg. The team also is adjusting to rookie coach Lane Kiffin's offense, may have rookie JaMarcus Russell starting at quarterback and really didn't improve its line.

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That's plenty with which to deal as the team attempts to push its rushing average to 4.0-plus yards per carry and 100-plus yards per game. Rhodes sharing the load with Jordan to help keep the latter healthy was supposed to lead to that kind of improved production. And if the team thought 2006 leading rusher Justin Fargas was the right complement to Jordan, it wouldn't have signed Rhodes. It's a good thing Jordan is up to speed and is working hard on his injury rehab, because he'll need to be good to go early. This mess will take on new forms through the middle of the season.

Falcons. Both 32-year-old Warrick Dunn (ankle) and second-year man Jerious Norwood (knee) are coming off injury-hampered seasons, and fullback Justin Griffith left for Oakland. Also, the zone-blocking system with which the Falcons have had good recent rushing success is gone, leading to adjustments both in running style and offensive line play. If Michael Vick sits, Atlanta will take yet another hit in its rushing production.

The best thing the Falcons can do -- see what their young players can do. Norwood needs to make his mark and win the job, because he's a big-play back around which Bobby Petrino can build his offense.

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Bills. Buffalo jumped on former Cal star Marshawn Lynch in the draft, taking him 12th overall, making him the second running back pick after the Vikings took Adrian Peterson at No. 7. I'm a lot more confident in what Peterson will do in a pairing with Chester Taylor in Minnesota than how Lynch will come out in a mix with five others, including Anthony Thomas, Shaud Williams and fellow rookie Dewayne Wright. It's a lot more complicated than feeding Willis McGahee isn't it?

Through everything, it seems most logical to start by giving Lynch 10-12 touches a game, with Thomas (short-yardage, goal-line) and Williams/Wright (third down) spelling him as situational backs. Eventually, Lynch's touches will be in the 20s, but the Bills need to see what kind of depth they have first. With only Lee Evans reliable in the passing game, they need to work more complementary cogs from the backfield.

Buccaneers. While Jon Gruden is doing the quarterback shuffle, there also are big concerns in the backfield, starting with the durability of Cadillac Williams and continuing with trying to fix some poor blocking. Meanwhile, Michael Pittman always seems to do well in relief but can't catch a break with more playing time. Williams needs to have a strong, healthy camp to help settle things.

Cardinals. If they are to graduate to the next level as both an offensive and overall power, they need better production and consistency from the running game so they can take full advantage of Matt Leinart, Larry Fitzgerald and Anquan Boldin in the passing game. Coach Ken Whisenhunt and offensive line coach Russ Grimm were the right hires to make that possible. Getting a new-look line to jell as run blockers is the first step, and then getting Edgerrin James to be down with having a lead fullback (former Brown and Saint Terrelle Smith). And if better situational execution requires both J.J. Arrington and Marcel Shipp to see a little more action, so be it. There's a lot of work to do in Cards camp.

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