The common recommendation is that kids should wait until they are 14-15 years old for a couple reasons. The first reason is because of the perceived stresses put on the immature skeletal system (i.e. open growth plates) by the curve. The second reason is that time spent practicing the curve ball usually means time not spent practicing the change-up.
I’d say most folks agree without argument about the second reason. The first reason, however, is debatable. Some claim that a properly-thrown curve ball places no more stress on the arm than does the fastball. The key there is the “properly-thrown” part. Even if coaches not the proper way to throw a curve, they also need to be able to teach it and, most importantly, they need to be able to verify it. Unfortunately, verifying with the naked eye is next to impossible because the important part happens when the arm whips forward and that happens too fast for the naked eye to see.
Also, there seem to be reports coming out from reputable sources saying things like “we have no evidence that the curve ball is more stressful on the arm than a fastball” and “the biggest cause of injuries is overuse”. I think people tend to or want to conclude from these claims that curve balls are safe. But I think that’s going a bit too far.
I will say that I believe in teaching kids the correct way to throw curves because they will otherwise learn incorrectly on their own. But it is also important to teach them to limit the number of curves they throw. I cringe every year when I see how many curves are thrown during the Little League World Series.
In sumary, my advice to you is to not get caught up in the wins and losses or playing for championship teams. Young kids need good coaching so they develop. And they need things to be kept positive. If these coaches pursuing your son are talking about teaching him a curve but are not saying anything about developing a change-up, that would be a red flag to me.
I highly recommend you check into the NPA
http://www.nationalpitching.net/][u]here[/u
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