Barnes (knee) participated in the Lions' OTA session Tuesday.
Barnes was injured on the first defensive series of the Lions' NFC Championship Game loss to the 49ers and never returned, but the knee issue clearly wasn't overly serious. He started 13 of the 16 games he appeared in last season, finishing with a career-best 81 tackles (42 solo), one sack and one forced fumble on a career-high 705 defensive snaps.