I agree the knee concerns are obviously worth proper due diligence, but is there any evidence or indication that it's something serious? I doubt many athletes get through a season without some sort of nagging issue, and I imagine his coaching staff was pretty sensitive to protecting him with nothing to really play for and an image to protect with Porter coming in next year (at the time). I can't find much on the actual injury other than it was a sore knee with some swelling that his coach said he could have played through in the short term if there was something at stake.