I've been reading all of these "TJ" threads for about a week now. There seems to be a lot of finger pointing and supposing...some of it based in fact and studies, some of based on anectdotal experience. Since my son also pitches and works toward a future of playing at the next level (wherever that might be), I too want to do as much as possible to prevent any injury or overuse.
Having said all that, I'm no "Carnac" (young folks can Google it...). What I do know is nobody has all the answers and we have to do our best to protect our players. As parents/coaches, we are their best advocate for almost all things (baseball and life). Although he hasn't commented on this posting I definitely agree with and respect J H's views on the subject.
In our first meeting three years ago, my son's pitching coach relayed his pearls of wisdom:
1) Your body is a machine. Any excessive repetitive motion will eventually wear out the part you're using.
2) Sound mechanics will allow you to maximize your potential and minimize your risk of injury.
3) There are only so many bullets in your gun. Some have more, some have less, but eventually everybody runs out.
4) You are a pitcher. The odds are you will eventually experience some kind of throwing related injury. My job is to make sure you're already in college or getting paid before that happens.
Our sons (or our players) chose this path, but they have no idea at the start what is in their best interest. It's our job to set boundaries and make things clear to whomever needs to know. I know some (not all) coaches may gristle at parents "telling them what they can and can't do with their players". To them I will say this: I make my position very clear before any season starts (HS, summer, scout, etc.). If we agree, great and they won't hear another word from me for the remainder of the season. If not, good luck with your team.
Okay, I'm off the soapbox now. Sorry for rambling.