I don't know what happened or the severity....I do know that I had a knee injury that required surgery and went through rehab and the whole 9 yards. I was playing basketball about a year later and kind of jammed it when I landed. It hurt a bit and kind of gave way, but it was much worse in my head that the actual pain. My knee was fine, it was just a scare that kind of came out of nowhere that was a shock to my knee and my mind as a quick reminder of the injury. I was fine the next day and haven't had any issues (save those that anyone after surgery on a joint has). Hopefully it was a similar situation and he will be back soon!