I was just alerted to this by an old teammate Jake Seiner who writes for MiLB and I think its worth a look and a bookmark to be used as reference.
MLB’s PITCH SMART, is (as you can see above) “a series of practical, age-appropriate guidelines to help parents, players and coaches avoid overuse injuries and foster long, healthy careers for youth pitchers.”
What I found most interesting so far is the pitch count guidelines chart (below).
There are also some great videos from guys like Dr. James Andrews and Brian Cashman.
As a pitcher who’s UCL is feeling more like Polly-O’s string cheese than a functional tendon these days, I think its worth a look.