Browns center JC Tretter tests positive for COVID-19
Browns' starting center to miss time following knee surgery
JC Tretter Retires From NFL After Nine-Year Career - Sports Illustrated
Former Browns center, NFLPA president JC Tretter retires National News - Bally Sports
The Biggest Story Lines of the 2021 NFL Offseason - The Ringer
Cleveland Browns release JC Tretter
J.C. Tretter, National Football League, News, Scores, Highlights, Stats, and Rumors
Why Minnesota Vikings weren't interested in JC Tretter
Former Browns Center JC Tretter Announces Retirement - Sports Illustrated Cleveland Browns News, Analysis and More
Former Cleveland Browns C JC Tretter retires