Buccaneers head coach told the media today that Doug Martin will eventually need surgery to repair his shoulder. Martin suffered a torn labrum two weeks ago and hasn't appeared on the field since, but the Bucs hope to strengthen his shoulder so he can play through the injury. Presumably he would then have surgery after the season ended.
Martin at least won't play against the Seattle Seahawks, and there's a decent chance he won't return to action at all this season.
In Martin's absence, rookie Mike James has been taking the majority of the carries while Brian Leonard acts as third-down back. The running game has been a problem all season, though, in part because of sub-par play by Davin Joseph and an injury to Carl Nicks. Play selection has been an issue, as well as the fact that teams don't need to respect the Bucs' passing game.
The Bucs will still be forced to run the ball, however, as they don't have the weapons to turn to a pass-first offense.