Posted by ESPN.com's Pat Yasinskas
First, the Bucs traded a seventh-round pick in 2009 to the Steelers for Mahan. Then, they turned around and traded Buenning to Chicago for a 2009 seventh-round pick. (Officially, the Bucs are saying both trades involve an undisclosed draft pick. But league sources said each trade involves a 2009 seventh-round pick.)
Mahan, who previously played for Tampa Bay, was expendable after losing his starting center job to Justin Hartwig. Mahan can play guard or center and the Bucs were thin on interior depth with starting guard Davin Joseph likely out for at least a month with a broken foot.
Rookie Jeremy Zuttah is expected to start in Joseph's place, but Mahan will give the Bucs a solid backup and flexibility on the interior.