49ers' Alex Mack announces retirement: 'I am so grateful to the game of football'
Center Alex Mack announces retirement after 13 NFL seasons - ESPN
Former Cleveland Browns C Alex Mack retires
49ers roster: How to replace C Alex Mack after retirement
Former Browns All-Pro center Alex Mack announces retirement after 13 seasons
Pro Bowl center Alex Mack to retire from NFL after 13 seasons: report
Regular Season Game 13 - Chiefs at Broncos (12-11-22) by Kansas City Chiefs - Issuu
Alex Mack retires: Seven-time Pro Bowl center ends career after 13 seasons with Browns, Falcons and 49ers
49ers need old-school running game to take pressure off QB Trey Lance
49ers center Alex Mack to retire
Former Browns' first-round pick Alex Mack retires from NFL
Morning Report: 49ers Rookies Recall Draft Day Memories