Every pitching prospect and current pitcher is an arm injury risk
Wonder WHY that is? My baseball "heyday" as a kid was from, say 1954-62. Only 16 ML teams (8 in each league), tons of starters going 9 innings regularly (or more, if needed). Could be there were more arm injuries than I recall; could be the pitchers (given the "science" of the day) continued to pitch while injured, throwing caution to the wind; or could be they tried to pitch to contact, the ball was deader, or who knows? But, whatever, you can't look at the stats below and not wonder why the big disparity wth today's pitchers (except for the few Max Scherzers of the game). Part of it HAS to be the money that is at play -- from both the pitcher's and the club's standpoints.
Take the pennant-winning 1954 Cleveland Indians staff and their starters (154 game season). Look especially at those Complete Game and Innings Pitched numbers! These guys didn't break down (except for Feller who was 36 years old in the 54 season).
1. Early Wynn 23-11, 20 CG, 270 IP, 2.73 ERA
2. Bob Lemon 23-7, 21 CG, 258 IP, 2.72 ERA
3. Mike Garcia 19-8, 13 CG, 258 IP, 2.64 ERA
4. Art Houtteman 15-7, 11 CG, 188 IP, 3.35 ERA
5. Bob Feller 13-3, 9 CG, 140 IP, 3.09 ERA