I don't know about that, but I do wonder whether the one size fits all approach is smart. If you're throwing upper-90s, then a 100 pitch cut-off seems reasonable. But someone like Fiers who sits in the low-90s and is more of a command pitcher could probably go a bit further than normal. From what I have read, it really has nothing to do with traditional "fatigue." Where oh, your tired so you should come out. (Think a basketball player dripping with sweat in the 4th quarter.) Injuries to pitchers can occur at a greater frequency when they modify their normal pitching mechanics. This happens at a more subconscious level - it isn't like the pitcher saying I am tired so let me change my arm slot. Fatigue is a factor but managers / pitching coaches should take more of a sport science view of their pitcher in games. If they notice changes in the body, that should alarm them for concern and not some arbitrary number of 100. One can be "fatigued" but his mechanics are still sound thus risk of injury isn't present. Where as another guy can be fatigued in the 3rd inning, and sub consciously making minor mechanical changes which can result in injury. I agree, the arbitrary 100 number seems completely made up.