Former Browns center JC Tretter retires, will stay on as NFLPA
'On to the next chapter': Former Cleveland Browns center JC Tretter
Former Cleveland Browns Center JC Tretter, Retires After 8 Seasons
49ers' Alex Mack announces retirement: 'I am so grateful to the
Former Browns center JC Tretter announces retirement from NFL
Former Browns, Packers center JC Tretter announces retirement
The Browns Can No Longer Consider A Familiar Option At Center
J.C. Tretter: News, Stats, Bio & More - NBC Sports
'On to the next chapter': Former Cleveland Browns center JC Tretter
Former Cleveland Browns C JC Tretter retires
7-time Pro Bowl C Alex Mack retires after 13 years in NFL