This happens all the time, and like others said if he wants a chance in the NFL he should have really considered it and probably done it.
IRRC a good example of this is Randall Cobb. I believe he went to KY because Fulmer told him he wanted him as a WR/athlete. Cobb is a HS QB, goes to KY and does pretty good at QB as freshman, but switches to WR after that. Then is a star as an NFL WR.
Kids, and their "sports" parents too, just can't see past their noses. QB at bama will get him in the league but hard to think he'll make it to long as a QB.