The Innings Bump: Is It *Actually* a Source of Injury Concern This Year for Pitchers?

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The Innings Bump: Is It *Actually* a Source of Injury Concern This Year for Pitchers?

Chicago Cubs

Generally speaking, baseball organizations have followed a philosophy – well, one among many – when working with young pitchers: you don’t bump a guy’s competitive innings too massively from one year to the next. Sure, there are developmental reasons not to do it, and there are external factors (season lengths) that guide it, too. But for the most part, that philosophy has been tied to wanting to develop pitchers in a way that protects their arms. If you bump too much too fast, the thinking has gone, you risk injury – either the sudden and catastrophic type, or the grinding-a-guy’s-shoulder-down type.

But is it actually true? Is this generally-accepted approach actually supported by the data? And even if it is, does it apply when you’re talking about established pitchers across, say, an entirely league, where there’s a need to bump guys up thanks to a pandemic?

Great read on that front in advance of the truly unique 2021 season:

There just isn’t any evidence that X amount of an innings bump increases injury risk by Y amount.

The best data available draws a subtle but important distinction: there doesn’t seem to be evidence that an innings bump, ALONE, increases the likelihood of injury, but pitching while fatigued or improperly ramped up does. So, then, it’s not hard to see how the two things could be tied together – you ramp up too quickly so as to reach a certain innings level, and you get hurt. Or you wear down later in the year earlier in your starts, which causes you to pitch while fatigued more often, and you get hurt. Neither case is strictly and solely about the innings bump, but there’s a relationship there.

So the lesson seems to be not that a guy like Kyle Hendricks couldn’t bump from 80-90ish innings last year to 180ish innings this year. Instead, it’s that you have to make sure he ramps up to a normal level of activity in a very normal way, and then you have to monitor very closely throughout the year to make sure he’s not out there pitching when he’s feeling fatigued. It just seems logical that a guy might be more easily able to get fatigued in August and September after a massive innings bump, though. So, again, that’s why it still seems like there’s going to be a relationship for a lot of pitchers this year.

And this is all idiosyncratic, too, of course. Things are going to be very different for Hendricks than they would be for a younger pitcher. Monitoring mechanics at a really extreme level is probably going to be more important this year than any in the recent past, because teams are going to be desperately trying to catch signs of fatigue (both that day’s fatigue, and the season’s fatigue) immediately upon it showing itself. Indeed, the teams that ultimately get the most out of their starting pitchers this year might be the ones that are the most aggressive in early pulls, even if it seems odd in the moment of the game.

Read the BA piece for much more on this.



Author: Brett Taylor

Brett Taylor is the Editor and Lead Cubs Writer at Bleacher Nation, and you can find him on Twitter at @BleacherNation and @Brett_A_Taylor.