Can Larry Johnson help in Miami's backfield?

Larry Johnson had only five carries in 2010 after being named an All-Pro in 2005 and 2006. (AP)

The last time Reggie Bush played a full 16-game schedule was his rookie season of 2006. Over the past two years, he has 106 combined carries, and he missed half the season last year due to injuries. Behind him on Miami's depth chart prior to Tuesday were rookies Daniel Thomas and Nic Grigsby, Lex Hilliard and Kory Sheets, who have 24 combined NFL regular season carries between them, 23 of those belonging to Sheets.

So the news that Miami went out and plucked Larry Johnson out of free agency shouldn't come as much of a surprise.

A little frustrating for Dolphins fans? Maybe. Their team let Ricky Williams and Ronnie Brown walk in the offseason, then traded draft picks to New Orleans for Reggie Bush and moved up in the 2011 draft to nab Thomas. Now, a little more than two weeks out from the regular season, the Dolphins have decided that wasn't enough.

Even if the Bush and Thomas additions were costly, it's hard to blame them. Miami, in an ideal world, would like its running game to dictate what its offense does -- especially given lingering questions over Chad Henne at quarterback.

That didn't happen last year. The Dolphins finished 21st in the league in rushing at 102.7 yards per game; their 3.7 yards-per-attempt average tied for 29th.

Cue the revamping of the backfield with the athletic Bush and hard-running Thomas -- the new version of "Thunder and Lightning" in Miami. Only Thomas had struggled in camp before a 52-yard performance in the Dolphins' second preseason game, and Bush still carries those durability concerns wherever he goes.

Johnson brings some red flags too, especially off the field, but Miami is banking on him being able to at least provide a few carries a game. The big issue now will be determining whether he's any more reliable than Bush or Thomas.

Johnson had all of five carries for the Redskins last season and averaged just 3.2 yards per carry in 2009 while playing for Kansas City and Cincinnati. In his prime, he was a powerful runner and valuable threat out of the backfield, a combination that would make him a perfect fit for this Miami attack. But he's been in rapid decline since a 1,789-yard rushing performance in 2005.

What he may allow Bush to do is move around the field, as opposed to lining up as the Dolphins' running back in a strict two-back set. Miami has proclaimed its desire to give Bush a shot at being an every-down back, but the reality is that he does his best work in space, and Miami isn't opposed to opening up the playbook -- this is the team that popularized the wildcat, for better or worse.

There figure to be more cuts as Week 1 approaches, which means that Miami may not have to settle for a Bush-Johnson-Thomas trio if something's not working. Steve Slaton could be a nice fallback for Miami if Bush gets banged up, while veteran Clinton Portis -- Johnson's ex-Redskins teammate -- as well as Laurence Maroney and Correll Buckhalter are also out there, should the Dolphins opt for a proven back.