did you see those bags of ice. He will be out for a while me thinks. Those hurt no matter who you are and can be quite serious even for what looked to be a not so hard shot to the knee.
I Remeber a couple of years ago in the Orange Bowl a Miama player like completly bent his knee backwards when he was tackled. Probably ended his career but im not sure. But i couldn't watch i was in so much pain after seeing it.