Does he really need a mentor at this point? I could see a veteran for the rb room in general, just for the been there done it factor, but I'm good going into camp with Williams Logan and Penny as the backups. I think Williams is a very good back and has shown enough to be given the chance to win the backup job.
Young guys can always use veteran leadership. Guys who has had long term success, playoff wins, super bowl experience, etc.