Moves like this later turn out to be stupid most of times yes. But than, one can never know what the future brings. So all you can say in a case like this is, good luck to the young man.
We've had players before joining top teams. Even in Milan there was Sandro Bloudek who was though of the next big thing here in Slovenija. Where is he now?
We have a couple in Inter at the moment too, by the latest news they are doing pretty well for their primavera, but who knows what will it be latter on.
Than there was Semler in Bayern. We all know how that turned out.
All in all, chances are small, but who are we to doubt him, therefore it's like I said, all we can do is whish him good luck.
P.S.
Sorry Diavolo, I can't really say anything about Uroš as I don't know him. He's just another one in the line of those extra specialy talented players.