I didn't know anything about a knee, but pretty sure he stayed out of the game after being lit up on that big hit. He played a couple snaps afterwards, but then left the game for good. Nobody has mentioned it, but they showed a quick shot of him on the sideline holding his head as he was helped to the bench (a trainer was holding/grabbing him by the top of his jersey...not a comforting hand on the back...a "let me help you stand up straight" hand on the back.)