BALTIMORE (WJZ) — According to coach John Harbaugh, the Baltimore Ravens’ Pro Bowl linebacker C.J. Mosley did not participate in the first week of offseason practices because he underwent shoulder surgery.

With Mosley sidelined, Albert McClellan worked at middle linebacker with the first-team defense.

Last month, the Ravens exercised their fifth-year option on Mosley, keeping the two-time Pro Bowl linebacker under contract through the 2018 season.

Harbaugh didn’t indicate any timetable on Mosley’s return.