Mahan was drafted in the fifth round (168th overall) of the 2003 NFL Draft by the Buccaneers. He played in 57 games with 36 starts with the Buccaneers from 2003-2006.
In 2007, Mahan started all 16 games at center for the Steelers.
The Buccaneers will be without right guard Davin Joseph for Sunday's opener, and Mahan played the position during his stint with the Bucs.
Buenning was a fourth-round pick (107th overall) by the Buccaneers in the 2005 NFL Draft. He has played in 25 games with 23 starts in his career.