San Francisco 49ers center Alex Mack retiring after 13 NFL seasons
What Happened To Alex Mack? (Complete Story)
Cleveland Browns: Alex Mack reportedly plans to retire - Dawgs By Nature
Meet Alex Mack -- Atlanta's question-spouting, erudite offensive rock
Alex Mack: Cleveland Browns going in right direction
Alex Mack retires: Seven-time Pro Bowl center ends career after 13 seasons with Browns, Falcons and 49ers
49ers Pro Bowl Center Alex Mack Makes Decision On NFL Future
Cleveland Browns general manager George Kokinas, left, introduces the Browns' new center, Alex Mack, to the media Sunday, April 26, 2009, in Berea, Ohio. In their first foray together at picking college