# What If Aroldis Chapman Threw Softer?

Aroldis Chapman doesn’t throw all the hardest pitches in baseball, but he does throw most of them. Last year, PITCHf/x captured 41 pitches of at least 102 miles per hour. Of those, Chapman was responsible for 27. He throws the kinds of rockets that make even rival spectators gasp, and indeed, the heat has long been his calling card. It’s one of the most exceptional abilities in the game.  Chapman throws a lot harder than just about anyone. But what if he didn’t?

In a sense, this is a hypothetical. In a sense, this can be investigated. What if we chopped a few miles per hour off Chapman’s average fastball? We can’t know for sure what that pitcher would actually be like, but we can make something of an educated guess, based on Chapman’s history. So let’s try it, just to see. Big thanks to Brooks Baseball for making this fairly easy.

We’re interested in Chapman when he throws in the 94 mph to 96 mph range, or so. But we can’t just isolate those slower fastballs. Things aren’t that simple. What if one of those slower fastballs came in a game in which Chapman was averaging nearly 100 mph? Then it would function almost as a pseudo-changeup, a minor change of pace. No, it’s better to focus on Chapman’s lowest game averages. I’ll try to keep the methodology to a short paragraph.

From Brooks Baseball, I exported Chapman’s single-game fastball velocity averages. In all, his fastball averaged 98.1 mph, with a standard deviation just less than 1.7. Subtracting the standard deviation from the average yielded just under 96.5 mph. I decided to isolate Chapman’s games in which his fastball averaged something below that mark. I was left with a sample of 36 appearances. Over these 36 appearances, Chapman’s fastball averaged 95.6 mph. So, rather than throwing like Aroldis Chapman, he threw like a really talented baseball player. Last season, John Axford’s fastball averaged about 95.3 mph. Luke Hochevar’s fastball averaged about 95.4 mph. This is a good fastball — a fast fastball — but a diminished fastball from Chapman’s established norm.

So what do the other numbers say? How did Chapman perform over his 36 slowest relief appearances? This is to be the basis of our educated guess. And, you know, things could be better. Over these appearances, Chapman threw just 59% strikes. He walked 19% of 151 batters. Over all his other appearances, he threw 64% strikes, and he walked 11% of more than 600 batters. The slower Chapman has been, the wilder Chapman has been.

But, my goodness, that isn’t everything. Slower Chapman also struck out 36% of the batters he faced. He allowed a contact rate of 67%. He allowed three home runs, for a rate which isn’t meaningfully different from his ordinary rate. Last year, 125 relievers threw at least 50 innings. Five managed strikeout rates of at least 36%, including Chapman. Slower Chapman has a higher strikeout rate than Trevor Rosenthal.

And there’s a very important consideration. Aroldis Chapman averages 98 mph with his fastball. We’re looking at a sample of games over which he’s averaged less than 96 mph. So this is selecting for games during which Chapman wasn’t quite right. Put another way: What would Chapman be if his 100% was throwing 95 mph to 96 mph? What we’re looking at are games in which he was throwing 95-96, but he wasn’t 100%. He’s dealt with shoulder fatigue before, and this can lead to performance issues that sometimes manifest as subpar control. That’s a likely explanation for the high observed walk rate. Slower Chapman is also not-normal Chapman, which means the numbers we see might reasonably represent the bare minimum, or so.

So let me summarize real quick. The question: What if Aroldis Chapman lost a few miles per hour? When he’s pitched below his norm, he’s walked a lot of batters, and he’s struck out a ton of batters. The walk rate might be explained by the fact that these are games in which Chapman wasn’t quite OK. And when he wasn’t quite OK, he still posted what would be one of the highest strikeout rates in baseball. So if healthy Chapman averaged about 95.6 mph, he might strike out even more batters. After all, it’s easier to do better when your arm feels better.

Here are examples of Chapman throwing in the mid-90s, for the hell of it:

When he’s thrown softer, Chapman still hasn’t thrown soft. A fastball between 95 mph and 96 mph is still a really good fastball, an above-average fastball even among the pool of relievers. I don’t know how to test what Chapman might be around 92 mph to 93 mph. When he’s thrown softer, Chapman hasn’t been literally unhittable, but he’s been about as close as any other pitcher. So there’s reason to believe that even if Chapman lost a few miles overnight, as long as he were healthy, he’d still function as a strikeout machine.

Mostly, I did this out of my own curiosity. But the other night I was wondering how long Chapman might be able to keep throwing as hard as he does. Velocity tends to diminish, and Chapman’s pressing against the upper extreme. Velocity-wise, Aroldis Chapman can’t be this version of himself forever. Performance-wise, though, it looks like he could still get the job done, even as a more ordinary hard thrower. Eventually, Chapman might be reduced to throwing 95 mph. And should that day come, opposing batters probably still will really hate him.

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Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

Guest
RC

” The slower Chapman has been, the wilder Chapman has been.”

Your correlation/causation is going the wrong way. I’d be willing to bet that he throws softer when hes wild, and not the other way around.

This is the problem with analysis based on data mining.

Member
Member
bdhudson

And your analysis is based on….?

Guest
maguro

It kind of makes sense intuitively. If I’m having trouble finding the plate, I’d probably dial it back a bit and see if that helps.

Guest
Philip

If I can throw as hard as Chapman I dial it up and try to throw it down the middle if my control is off. At 95 you need a little more precision.

Guest
RC

Then post some evidence of the claim.

The explanation with the highest probability is that Chapman is like pretty much every other pitcher on earth (barring knuckleballers), and control issues are caused by mechanical inconsistency/release point inconsistency, and that dialing back effort leads to more release point consistency, not less.

The only explanation that makes sense for throwing slower leading to less control is injury, and if hes throwing slower because of injury, then using this data to predict what sort of pitcher he’d be maxing out at 95 (and not injured) is a giant waste of time.

Guest
Catoblepas

woah woah woah. you start your post off with “Then post some evidence of the claim” before asserting “The explanation with the highest probability is that Chapman is like pretty much every other pitcher on earth” with no evidence! why? he’s a person, but he definitely isn’t like pretty much every other person on earth, in that he can throw a ball 104 miles per hour. that also makes him unlike almost every other pitcher on earth! so why would his control issues function the same way you claim (again, with no evidence) every other pitcher’s do? if you wasted your time by reading an article, that’s your fault. the free content-producer is not to blame.

Guest

The fact that he throws faster than almost everyone doesn’t make anything he does fundamentally different. There’s absolutely no reason to believe that the normal things pitchers do no longer apply to him.

If you think that Chapman is fundamentally different from other pitchers, that’s an extreme claim, and the burden of evidence is on you.

Guest
RC

Pretty much every interview I’ve ever heard with a pitcher that talks about being wild.

They pretty much all say they dial things back and focus on their mechanics.

Guest
pinch

ugh, analysis based on data mining, amirite? give me assumptions of uniformity with no data to back them up any day.

Guest
Iron

Thanks for the explanation Jeff.

Guest

I know what you’re saying, but correlation doesn’t imply direction.

In any event, I think another likely explanation for the correlation between Chapman’s velocity dip and control issues is that they are spuriously correlated. That is, they are both correlated to a 3rd variable that actually is cause, namely fatigue.

Anecdotally speaking as a Reds fan who has watched him for a few years now, while Chapman can go a few innings at a time pretty effectively, he fatigues pretty reliably when pitching in back-to-back games (or more). If we’re selecting for games with low average fastball velocity, we’re likely selecting for fatigue. A “weak” Chapman is going struggle to maintain his mechanics.

Furthermore, we know that Chapman is quite proud of his velocity. I don’t think it’s crazy to speculate that he’s particularly prone to over-throwing when fatigued (in an attempt to recapture velocity), which would also show up as a control issue.

Lastly, I wonder if this a special function of guys with very top end velocity as a result of the timing required to hit 100 mph. Is it possible that as you approach ~100 mph, you start getting to the point where hitter ability to judge pitch location rapidly deteriorates? In that environment, you may have hitters guessing more often, swinging at poorly located pitches or at “fastballs” that are actually sliders (90 mph sliders).

But as velocity drops, the hitters have more time to read those pitches and choose to lay off more of them. What shows up as worse “control” from Chapman, could just be better pitch recognition from hitters. Of course, he still has nasty stuff and 4 balls to work with in each PA.

So I’d because curious:
– Do his low velocity appearances come with less rest?
– How do hitters’ swing% change?
– How does his pitch mix change when he doesn’t have 102?

Guest
bilbovibrator

u smart dawg

Guest

I wouldn’t mind betting that Chapman throws softer because his mechanics are out of whack. Throwing the hardest out of a population of hard throwers will not be just about strength and effort, but very subtle mechanics will come into play as well. I am guessing that when those mechanics get out of sync, he is not as accurate, and throws softer as well. Little changes, especially to body positions and rhythm will yield large charges, such as a 5% reduction in velocity.