Believe it or not, Ricky Williams still has a little gas left in the tank.  HB isn't a pressing position presently, but sooner or later the Bengals are going to have to deal with a potential suspension of Benson.  Williams is a similar HB and might step in nicely if in fact Benson is suspended, and he might even be helpful giving Benson a few reps off which will also help keep him healthy.  Bernard Scott and Brian Leonard are good, but can they carry the load without Benson?  I can't expect Williams would call for much more than 1 year at league minimum.  So why not?

Naturally, we have other positions that are more important to fill right now, but just throwing it out there.