Dolphins sign Larry Johnson

ESPN.COM

So the Dolphins signed Larry Johnson today. Does anyone know WHY??. They cut Kory Sheets, which I can see why, but to sign Larry Johnson??. It doesn't make sense to me at all. Especially if they didn't re-sign Ronnie Brown or Ricky Williams because they were "washed up". Johnson has not done much the past few years. I mean the only thing he's been good at is getting into trouble with women. If the coaching staff was nervous about the RB situation, and wanted a veteran presence, then why let Ricky go?. He never cared about starting or getting so many carries. All I know is that Johnson has A LOT  to prove to the fans that he can still play ball and stay out of trouble(which means he needs to stay away from South Beach). I don't know how much of a "help" he can be to Bush or the rookie Daniel Thomas. Not much of an outstanding guy in and out of the locker room.