This is EXACTLY what I did to my knee this spring. Same exact thing. Ultimately I was able to play the rest of my season without any pain or any restrictions, the only concern is that his knee has the potential to buckle and lock in a less than 90 degree angle, in which case he's f***ed. The good thing is that the arthriscopic surgery that I had is probably the same thing he'll have, except he'll have to have the torn piece removed. They were able to repair my meniscus, but my recovery time is MUCH much longer than if they had just taken the torn piece out. Recovery time for a removal is about 48 hours on crutches, then a few more days getting used to moving your knee around. They were able to repair my meniscus, so my recovery time is about 5-6 months. I've spent 4 weeks on crutches, and I can walk around on Thursday with my leg in a brace which will keep it completely straight. The good thing about this is that Manny can play through this, the bad thing is that if something happens to him while he's playing, it's going to be incredibly painful and he'll have to have the surgery immediately.