Kerby Joseph's Knee Injury Fuels Retirement Rumors

Detroit Lions safety Kerby Joseph, 25, was placed on the Physically Unable to Perform (PUP) list after a knee injury limited him to six games in the 2025 season. Outside physician Jimmy Liao, a Lions fan who provides public injury analysis, warned that the severity of the knee problem—potentially involving articular cartilage damage, swelling and reduced joint mobility—could force Joseph to consider retirement to protect his long‑term health. Liao emphasized he has not examined Joseph, reviewed his medical records, or consulted the team’s doctors.

Joseph has posted workout videos showing short sprints and athletic movements, but analysts note that training sessions differ from the daily demands of NFL competition. The speculation has heightened concerns among fans and media about the safety’s career outlook, though the Lions have not confirmed any decision.