Which pitcher in baseball has the best fastball? Aroldis Chapman. This isn’t one of those everyone’s-opinion-is-valid situations. The answer is Aroldis Chapman. While I’ll grant that the real, absolute answer is unknowable, based on the things we know, Chapman has the best heat, and that’s basically why he’s long been one of the best relievers. He’s thrown a slider, too, to keep people honest, but he’s thrown it just often enough for honesty, and he’s thrived with the heater. He’s the owner of the fastest pitch thrown in the PITCHf/x era.

So you can imagine what it’s like to face Chapman in the box. I’m kidding, it’s unimaginable, and you should be thankful for that, because you don’t want to experience what those players experience. Imagine preparing for that kind of fastball. Imagine not knowing where it’s going to be. Imagine having the sense that maybe, just maybe, he’s going to throw a wrinkle. But you basically have to sit fastball. There would be two worst nightmares: a fastball high and tight, and a changeup.

Uh oh.

(Source: Texas Leaguers)

Back in spring training, Chapman was throwing a lot of a changeup. Then he got hurt, badly hurt, horrifyingly hurt, then he got better and came back. Since coming back, Chapman has thrown a lot of a changeup, that he hasn’t thrown before. When he was a starter, he had a changeup in his repertoire. When he shifted to relief, it basically disappeared, and if he ever threw a change, he didn’t do so more than a handful of times. The changeup, now, is just part of his arsenal, and it hovers around 90 miles per hour. Which means Aroldis Chapman, an all-time dominant reliever, has increased his repertoire by 50%. And so far this season, he’s struck out 54% of the batters he’s faced.

Some of the time, it’s like nothing has changed. Chapman has still been the familiar Chapman against left-handed hitters, which is to say he’s been fastball/slider and untouchable. But, a year ago, against righties, Chapman threw 86% fastballs and 14% sliders. This season, against righties, he’s thrown 57% fastballs, 27% sliders, and 16% changeups. His fastball rate is way down on the first pitch. It’s way down with the batter ahead. It’s way down with the count even. It’s way down with the pitcher ahead. It’s way down with two strikes. Aroldis Chapman isn’t a completely different pitcher, but he has evolved in a way that isn’t some coincidence, that isn’t statistical noise. There’s no small sample size to worry about, here — Chapman just has a changeup now. He likes it.

So does Bryan Price:

“And it’s a good changeup; it’s a really good changeup. I do believe that it’s going to be a much more substantial part of his repertoire than we’ve ever seen before, because not only is it a good pitch, it’s a controllable pitch for him, and it certainly plays well for a guy on those days when maybe he doesn’t have that plus-plus-plus velocity.”

Interestingly, the changeup hasn’t been used as a putaway pitch. Chapman’s thrown eight with no strikes, 22 with one strike, and five with two strikes. It’s been a weapon to get him ahead or put him in a putaway count. There’s a confidence in that pitch, already, that one might not expect.

Unsurprisingly, the pitch has gone for a lot of balls. Batters haven’t offered too much, and Chapman is still harnessing the movement. But here’s by far the clearest idea of what the pitch can do for him, and for the rest of his repertoire. Against the changeup, batters have attempted 14 swings. Of those 14 swings, precisely zero have made contact.

In other words, Chapman’s changeup is running a 0.0% contact rate. This is being written before Wednesday’s Reds game, so maybe this info’s already outdated, but this is at least what the info looked like once. The changeup has left batters utterly helpless, just like you’d think a changeup would do when it’s coming from a guy who throws 100 with a sharp, biting slider. At a certain velocity threshold, you just can’t hope to see and react. If Chapman isn’t there, he’s close.

Here’s a changeup to put a batter away:

Here’s a changeup to start a guy off:

Here’s a changeup to get back in the count:

Here’s a 100mph fastball right after a changeup:

Lefties, at least, have the good fortune of not having to deal with this. They just have to face regular old Aroldis Chapman, with the platoon disadvantage. Righties now see Chapman as a three-pitch pitcher, and what’s more is he’s avoiding predictability in any and all counts. The fastball’s always going to be more likely than anything else, but there are a pair of real alternatives, and the changeup rate might only increase still should Chapman develop a greater ability to spot it. He might not even need to be able to spot it that well. Ryan Braun, above, missed a first-pitch changeup middle-middle. There’s a difference of 10-12 actual miles per hour that looks like even more than that when you’re comparing high fastballs against low divers. By perception, the difference could be as much as 20 ticks, and then there’s the slider too.

In the short term, Aroldis Chapman should be better for this. It helps when you can add a pitch that batters almost literally can’t hit. They’ll adjust to him to some extent, but adjustments can accomplish only so much. In the long term, Chapman might be better able to stave off decline, and this isn’t going to mute any of the arguments that he should convert back to being a starter. In addition, it’s possible that, by throwing fewer burners, Chapman might do something to preserve his arm. This is already the start of a new chapter. We don’t know how it’s going to read, but we have some ideas, and a few of them are borderline inconceivable.

Already a man who could do the impossible, Aroldis Chapman has added a twist. He probably didn’t need to, but it’s also probably not going to hurt, and it might open some new doors. The man with the best fastball in baseball is leaning on his fastball less often, and he’s pitching better than ever.

He’s also throwing harder than ever. So, you know. There’s that part, too.