Starting left guard Dan Buenning joined the growing list of Bucs whose seasons were ended by injuries.
The injury Buenning sustained to his right knee during Thursday's loss at Dallas will require surgery this week. The team placed him on injured reserve Monday.
Buenning started all 17 games as a rookie but has been hurt most of this season. He missed two games and failed to start two others because of a high ankle sprain. His return three weeks ago helped spark Cadillac Williams and the ground game.
Other starters on IR this season: quarterback Chris Simms, right tackle Kenyatta Walker, cornerback Brian Kelly and defensive end Simeon Rice.
Sean Mahan will finish the season at a left guard. Mahan has started seven games this season.
Mahan, who started every game last season at right guard, indicated he is capable of switching.
"Everything is backward, so you have to relearn your technique," Mahan said.
TRANSACTIONS: The Bucs signed center Nick Mihlhauser to the active roster off the Chargers practice squad along with safety Donte Nicholson, who played for the Bucs as a rookie last season, mostly on special teams. Nicholson said he worked out with seven teams.
"When I got the call, I was just happy to be back," he said. "It was real tough on me, just being away from these guys. These are pretty much my only friends in this town, too. It was hard. But a lot of them called me and kept my spirits up and told me everything was going to work out in time and something would come your way. Sure enough, this did."
Added to the practice squad were defensive tackle Darrell Campbell and cornerback Carlos Hendricks.
WYMS HOPEFUL: Defensive tackle Ellis Wyms, who missed the past two games with a high ankle sprain, said the long weekend was beneficial. He participated in Monday's light practice but wasn't certain he'll be ready to play Sunday at Pittsburgh.
"I moved around some and it felt a whole lot better, but practicing in non-pads is a whole lot different than going out there against the Pittsburgh Steelers for four quarters," Wyms said.
Staff writers Stephen F. Holder and Rick Stroud contributed to this report. Joanne Korth can be reached at email@example.com or (727) 893-8810.