Tampa Bay coach Jon Gruden joked Monday that he thinks he has the phone number for Hall of Fame running back Barry Sanders. But the situation at tailback is hardly a laughing matter for the Bucs, with the loss of Michael Pittman to an ankle injury suffered during the team's loss at Indianapolis on Sunday afternoon. Pittman will miss 6-8 weeks, Gruden acknowledged, and his absence will likely force the Bucs to add a veteran tailback either through free agency or in a trade. Fourth-year veteran back Earnest Graham, a former undrafted college free agent form the University of Florida, now becomes the starter. The backup will be rookie Kenneth Darby, who was elevated from the practice squad last week.