How Aroldis Chapman has turned things around in August

Aroldis Chapman had a tough month of July. He blew three of his seven save opportunities, pitched to an 8.41 ERA and walked 11 batters in 8.1 innings. Although every pitcher can go through slumps, there’s always extra concern with Chapman as he ages and gradually loses his top weapon, his velocity.

Fortunately, Chapman has rebounded in a big way this August. Through eight games, he has earned the save in all of them while striking out 13 and only walking two batters over eight innings. With the postseason just around the corner, getting Chapman back on track is crucial to the Yankees’ success.

How has Chapman turned the page? In July, some of Chapman’s mechanics got a little out of whack. This month, those figures have stabilized and he is back to being the dominant pitcher that he has been for most of his Yankees career.

First, let’s look at Chapman’s fastball. In July, his heater’s spin rate declined. Interestingly, Chapman’s spin rate was only lower than this once in his career, during his equally-disastrous August 2017, a period that saw him briefly removed from the closer’s role. It’s hard to determine why his spin rate declined, but there’s definitely a correlation between it and his performance, considering his similar issues two years ago.

Chapman’s fastball velocity also dipped to an average of 97.2 mph for the month, which was the second-lowest average of his career. Moreover, Chapman wasn’t using his fastball like he’s capable of, either. Below, check out his heat map on fastballs in July:

See how it’s just a predictable blob, right in a hitter’s happy zone? Compare that to his fastball placement this month:

It’s much more scattered, but here that’s a good thing. It’s harder to predict, as Chapman has specifically pitched inside to righties significantly more. When you combine 100 mph velocity with placement on the inside corner, it’s almost impossible to hit. When Chapman is using his fastball to intimidate hitters, he’s pitching like his best self.

Additionally, Chapman ran into some trouble with his slider in July, too. Although his spin rate didn’t suffer, his velocity sure did. Chapman only averaged 84.7 mph on his slider in July, the third-lowest figure of his career. He also threw the pitch exceedingly often, the third-highest total he has thrown in any month. That’s a recipe for disaster.

However, Chapman’s slider wasn’t suddenly hittable. Instead, he ran into a control problem. His walk rate on the slider was over 18 percent in July, the third-worst total of his career. You can really see it here, in his July heat map on sliders.

It’s all over the place! Now, look at Chapman’s heat map on sliders in August:

The pitch is much more focused, and placed in a good spot at the bottom of the strike zone, bending in on righties and away from lefties. While a pitcher can certainly just “lose” a pitch for a little bit, something else caused Chapman’s sudden slider ineffectiveness.

This chart shows Chapman’s vertical release point on his pitches over this year:

Notice how the blue bar (his slider) has gotten higher and higher, but has now started to decline back to normal? That shows that Chapman’s mechanics on his slider were off. When you compare it to the black line, his fastball, which has stayed steady all year long, the variation in his slider mechanics jumps out instantly. Luckily, he seems to be getting back to normal this month, while also throwing less sliders overall.

Chapman is a huge X-factor for the Yankees this postseason. He’s the club’s best reliever, but he can also be prone to a few mechanical issues that take a while to iron out. Hopefully, Chapman has left his difficult July behind him and looks ready to backstop the Yankees throughout a playoff run.