Maybe they are trying to develop that part of his game. He would be far more use full player if he was a genuine goal threat and had instincts to run in behind instead of always looking to drop back and get on the ball in space. That is the thing with Youth football, we might score more with a 6ft striker every game but the objective is to create 1st team players and if Diaz can play anywhere across the front he stands much more chance. He does need to work on it though.
While I understand that perspective, I don't agree that he should play 'up top'. He's an attacking midfielder or number 10 and should be trained to add goal threat to his existing talents, while maintaining the position in which he is a potential world star.