Lately my son’s fastball as been moving in on right hand batters like a screw ball. He is a right hander. At release is palm is pronated facing third base completely. Is this a problem? Will it lead to injury? Or a good thing. Thrown 4 seam it hook sharply in. with 2 seam it hooks down and in. He has had trouble locating outside fast balls on right handers. Sometimes when he tries that it winds up right in the middle of the plate. If he continues with these machanics what stratagy should he use facing right and left handers. He throws a good change, curve that does break down and away on right handers.