Driveline Baseball
I'm just going to list these links. Well worth your time for background on pitcher development / injury rehab.
https://www.beyondtheboxscore.com/2017/6/13/15782420/kyle-boddy-drivelin...
https://www.beyondtheboxscore.com/2017/6/13/15783088/kyle-boddy-drivelin...
https://www.beyondtheboxscore.com/2017/6/13/15783536/kyle-boddy-drivelin...
UCL tears are no longer an end to a career, but so much more is going on.