used to hit .300...I could get your point if had gotten hurt because he was overpitched at the time of the injury...but if he wasn't I don't get your point. Is he allowed to throw any time he "doesn't need to?" You could say throwing the ball from anywhere but the mound is an unneccesary risk.
Some coaches would never let a blue-chip pitcher play outfield just for that reason. Why let a kid try to gun down a runner at home from 250 feet away? That seems like far more of a risk than pitching.