My oldest son had the transposition surgery and my youngest "just" the decompression - neither competes at the level of your son, but I agree with the do the rehab part, listen to the PT's, and don't try to rush it. The elbow is immobilized for a while. Trust the PT's and that recovery happens. The older only played baseball for another year or two after at HS, the younger thru a couple years at D2. Neither has said anything about it being problematic afterwards. Unlike perhaps TJ or shoulder type surgeries, this one isn't cutting, stretching, or replacing something - it's either just cutting a sheath that the nerve runs in thus making it not constrict on every throw or it's moving it from under the elbow to a channel inside the elbow. The transposition requires a bit more work obviously and they'll usually clean up any scar or bone spurs that are probably rubbing against the nerve causing the issues. I'm not a doctor, just recall the description and cringing a little bit.