He got hit in the back of the knees and his knee buckled — but they at least buckled in the direction that the knees are SUPPOSED to bend. You couldn't see any obvious impact on the side of the knee or a hyperextension, and hopefully those knee braces they wear prophylactically did the job they are supposed to do.

He's a massive guy, so when you take his knees out he's going to drop hard, and the fall could result in some knee damage. But hopefully it was just a strain and with rest and a little recovery he'll be ready to roll.