@shoveit4ks
That is awesome. I think that partially goes back to you have to have the genetics and athletic ability and it sounds like you son has plenty of that. It also sound like he has developed the "right" (for no better term) way in that he had that natural ability and probably smooth mechanics that got him to mid 80's, then as his body matured more between sophomore and junior years and he started working out more.
I'm saying those kids are the exception, not the rule, I'm assuming he is wanting to get drafted and not do the college thing.
I just saw this and thought it was interesting:
2015 roster makeup
2 year college: 69
4 year college: 397
High School: 204
International: 197 (not sure of ages of these guys)
That is 69% of current rosters, excluding international players were drafted from college.