Him opting to not play in the Kentucky Combine is something I am seriously wary of.
Why does it matter though KOC has already seen him work-out in person. Regarding his knees though, I have heard some stuff on them, but I did some re-search and some guy named Blake Griffin has "bad knees" coming out of Oklahoma his sophmore year too. I think Griffin is doing pretty good right now, hey he even won rookie of the year.