Hmmm... and your solution would be: every time a player throws a tantrum (unheard of in professional sport, eh?), just let them go to the competition.
Way to get respect from the other players. And the other teams. And your members too.
The only childish thing here is signing a contract (no one forced him) and then whingeing after 2 months because your best mate has moved to a different school... i mean team...