Left guard Mike Iupati took part in every practice this week and is listed as questionable on the team's injury report. "Still a possibility," Jim Harbaugh, always eager to keep injury news vague, said of Iupati playing Sunday against the Buccaneers. If Iupati, who sprained his left MCL on Nov. 17, cannot play, Adam Snyder would make his fourth straight start at left guard. Cornerback Tarell Brown (ribs) also is listed as questionable, as is receiver Mario Manningham (knee), who has not caught a pass in the last two games. Tramaine Brock is likely to start at right cornerback in place of Brown.