Note to coaches. Don't tell a young kid that he cannot do something or will never be something. Especially when the kid is only 12 years old.
My son had been the primary catcher for his previous team. He played off and on in right field too, but wanted to play infield (2nd base) on occasion. He wanted to become more versatile for high school.
I told my son to approach the coach and ask him if he could get a chance to play 2nd base in practices with a chance to earn some playing time in games. His ex-coach, chuckled at him and said, "Nic your not an infielder" and turned away. My son walked away without comment, but was absolutely furious. He was close to tears telling me the story in the car ride home from the practice. I wanted to approach the coach and plead my son's case, not for playing time but for respect and a chance. My son forbade me. I told my son to hang in there that this was our last year with this coach.
This season, my son is on a new team with a new coach. He has been playing second or catcher all year long. Tonight he was at second base and had a terrific game, a once in a lifetime type of game.
My son made 12 of the 27 outs at second base. He fielded 8 grounders to get 8 force outs at first base. He also caught 2 pop ups and 2 line drives, one of which was spectacular and turned out to be a game saving grab.
He did not make a single error. In fact, he has only made one error at second base all year long.
The Main Point
Coaches, I am going to state the obvious. Kids change continuously. Their bodies, their confidence level, their attitude and their courage can and will all change year after year, maybe even month after month. As such, don't pigeon hole a kid into a position or prevent a kid from practicing a position he wants to learn. Who knows maybe he will be spectacular at a position.