When the Royals signed Aroldis Chapman to a one-year deal as a free agent this offseason, it was a polarizing move among many Royals fans.
Chapman has certainly had his issues off the field, which included domestic abuse allegations nearly seven seasons ago, and his being left off the Yankees playoff roster in 2022 due to him missing a team meeting/practice at the end of the year. Those two items alone would warrant many clubs not even considering signing Chapman to any deal this offseason, let alone a guaranteed Major League one.
While the off-the-field stuff made the Chapman deal questionable, his on-the-field play last year wasn’t exactly sterling either.
In 43 games and 36.1 IP with the Yankees last year, the 35-year-old Cuban lefty posted a 4.46 ERA and a -0.2 fWAR, both the worst marks of his career, according to Fangraphs. As a result, it’s not a surprise that Chapman was not just released by the Yankees at the conclusion of last season, but he also ceded his closer role to Clay Holmes in 2022.
A big issue for Chapman in 2022 was a massive decline in his chase and CSW (called-strike plus whiff) rates.
Here’s a look at Chapman’s plate discipline metrics over his career, and notice how in 2022, the O-Swing percentage and zone percentages went down, while the contact rates went up. This affected his overall CSW rate, which was 30.9 percent, his lowest number since 2017, his first season with the Yankees.

As a result of declines in CSW and chase rates, and an increase in contact rate, Chapman’s strikeout numbers also plummeted in his final season in the Bronx. His K percentage dipped to 26.9 percent, and his K-BB percentage was 9.3 percent. The latter was not just a career low, but a 14.9 percent decline from his mark in 2021.
Safe to say, Chapman was a mess in 2022, and that explained why there wasn’t much of a market for his services from other clubs this past winter.
That said, the change from the Bronx to Kansas City has done wonders already for Chapman through eight games this year.
In three appearances and three innings pitched, Chapman has struck out six batters and has only allowed one hit and one walk this season with no runs allowed to boot. While Scott Barlow is still clearly the closer on this Royals squad, Chapman has emerged as an electric setup man for the Royals who could give this club a dominant relief pair in the 8th and 9th innings.
So what has been the big difference for Chapman in 2022?
Well, a lot can be tied to his four-seam fastball, and the extra life and velocity he has put on the pitch with the help of the new coaching regime in Kansas City.
The Velocity Returning on Chapman’s Four-Seamer
A big issue that correlated with Chapman’s lack of success in 2022 was his lack of velocity on his four-seamer.
Last year, he only averaged 97.5 MPH on the four-seamer, which was a career-low, according to Baseball Savant. While his velocity still ranked in the upper percentiles of the league, it is also a pitch without a lot of great movement. So much of the pitch’s success is tied to how hard and often Chapman can simply throw it by hitters.
According to Pitcher List PLV data, Chapman’s four-seamer only had a PLV of 4.62, which ranked him in the 16th percentile for the pitch. He also struggled to make the four-seamer a quality pitch, which is not a good sign for a pitch that he threw 55.5 percent of the time.

At 35 years old and coming off a season when his four-seam velocity was at the lowest of his career, it makes sense why the Yankees opted to not bring him back or many other teams came calling this winter.
On the other hand, according to Inside the Crown writer David Lesky, the Royals opted to sign him to a one-year deal because the new regime saw something in Chapman’s mechanics last year that they felt he could fix with their help.
Here’s exactly what Lesky said in his piece:
I did talk to someone who I trust who has very good intel into what the organization is doing. He says there is a fixable mechanical issue that they have found and believe they can fix. I think it’s very easy to scoff at them fixing someone’s mechanics, but remember, this is a new big league team of pitching instructors. Nobody knows if they’re capable of something like that, though it sort of sounds like they’ve got the right mix from what you hear around the game.
“Crown Jewels: Aroldis Chapman is a Royal, Brady Singer is Fighting Arbitration and More” by David Lesky; Inside the Crown
So far this season, it sounds like Brian Sweeney, Zach Bove, and the Royals pitching coaching team have helped Chapman fix that mechanical issue, and suddenly the four-seam velocity is back, as Royals fans can see in this average pitch velocity chart, via Savant.

Chapman’s four-seam velocity so far has been at its highest mark since the 2017 season. He also is generating a whiff percentage of 70 percent and a CSW rate of 50 percent on the four-seamer, which put him in the upper percentiles of the league, according to Pitcher List data.

Lastly, we have also seen a bump in Chapman’s K percentage this year. Chapman is posting a K percentage of 54.5 percent this year, a major improvement. Based on his rolling K percentage chart, via Savant, his K rate definitely is in a much better place now than it was a season ago in New York, especially at this time last year, when his K rate was in the 10-15 percent range.

And while the data certainly backs up Chapman’s rebound in Kansas City in his first few outings this year, the tape itself is certainly impressive.
Here’s Chapman carving up Twins hitters for three-straight strikeouts in his appearance on April 1st.
And here is him on April 4th against the Jays just completely overwhelming Toronto’s Bo Bichette with 100+ four-seam fastballs which generate a three-pitch strikeout.
Safe to say, the velocity on the four-seamer is back, and as a result, vintage Chapman has also returned in Kansas City, even though it may only be for a few months before he’s eventually traded by the Trade Deadline.
Are There Any Concerns?
I have talked a lot about the four-seamer in this post, and haven’t mentioned anything about his other secondary offerings so far in this post.
It makes sense considering that he throws the four-seamer 60.9 percent of the time. I haven’t pointed out the other pitches because Royals fans haven’t seen a whole lot of other pitches from Chapman so far this year in his first three outings.
That said, so far this year, the four-seamer has helped make his other three pitches (sinker, slider, splitter) even more effective, which can be seen in the run value data of his pitch repertoire, via Savant.

In his latest outing, Royals fans can see that not only were the velocity and spin up on all of his pitches, but he also saw impressive strike data on all four of his pitches as well.


If there is one concern that Royals fans should have or be paying attention to in future Chapman outings, it may be how hitters are making contact against Chapman when they do connect with the ball (even though that isn’t often).
Here’s a look at Statcast percentiles, and notice how Chapman ranks in the lower percentiles of average exit velocity as well as hard-hit rate.

Add those hard-hit metrics, along with a lackluster chase rate, and it will be interesting to see what could happen to Chapman’s overall numbers, especially if the four-seam velocity should dip over the course of the season. Chapman can overpower hitters when the velocity is in that 100+ range, but he’s not going to get hitters to chase out of the zone, whether it is with the fastball or other offerings, if the velocity isn’t there, it appears.
Again, these are only minor concerns for now. With Chapman’s velocity, batters are going to generate hard contact naturally. Furthermore, it’s been a trend over his career, even when he was at his peak during his Yankees years, though it has been more alarmingly up over the past two seasons, which can be seen in the Savant rolling chart below.

The more Chapman can neutralize that hard-hit contact, and also, perhaps generate more chases out of the zone, the more comfortable Royals fans can feel about Chapman moving forward in 2023.
But for now, it’s been a tremendous start for the 35-year-old reliever, and his presence could make the Royals bullpen one of the more underrated groups in the American League.
Photo Credit: SI Fan Nation
[…] Kevin O’Brien writes that Chapman’s four-seamer has been key to his success. […]
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[…] was thought to be the Royals’ most prized relief pitching piece, and he probably still is considering his premium velocity and strikeout ability. However, Chapman has had some knee issues lately, which is a reason why he wasn’t utilized in […]
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