Michael Wacha is Looking Better Than Ever

[Kevin O'Brien]

Image courtesy of Peter Aiken-Imagn Images

The Royals' starting pitching has been a strength of the team this season, despite their 7-9 record (entering Tuesday's game against Detroit). According to Fangraphs, the Kansas City rotation ranks 4th in ERA, 7th in WHIP, and 11th in fWAR. That stellar starting pitching is a big reason the Royals have been able to somewhat overcome their mediocre offense (and "mediocre" is putting it nicely). 

Here's how the Royals' starting pitchers have broken down this year individually, as of April 14th.

Seth Lugo and Kris Bubic have gotten off to excellent starts this year, as evidenced by their 1.53 and 2.50 ERA marks, respectively. However, Michael Wacha has clearly been Kansas City's best starting pitcher through his first three starts of the 2026 season.

In 21 IP, which leads all Royals starters, Wacha has a 0.43 ERA, a 7.3 K/9, and 3.05 FIP. He has also produced excellent marks in many of his Statcast categories this season, including wOBA, whiff%, CSW%, and O-Swing%. A full breakdown of his Statcast percentile rankings so far this season is below, via TJ Stats.

Wacha's wOBA ranks in the 94th percentile, his BB% ranks in the 71st percentile, his whiff% ranks in the 82nd percentile, his CSW% ranks in the 96th percentile, and his O-Swing% ranks in the 86th percentile. Wacha is producing these solid metrics despite ranking in the 35th percentile in fastball velocity and 11th percentile in TJ Stuff+. That shows the stellar command the veteran has demonstrated, a good sign for the Royals' pitching staff this season.

However, how has Wacha been successful so far through three starts? What have been the key pitches for him this season, and what could his outlook be for the remainder of 2026? Let's break down those important questions regarding Wacha below.

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Wacha Leading With His Four-Seamer (And Finishing With Change)

Wacha is not known as a high-strikeout pitcher due to his mediocre stuff profile. Overall, he's sporting a 96 in TJ Stuff+, and he has only one offering over 100 in TJ Stuff+ this year (his slider). However, that hasn't stopped him from producing strong chase and whiff rates this season, as illustrated below via his TJ Stuff summary.

Wacha is producing a chase rate of 34.3% and a whiff rate of 29.5%, which are both well above-average marks. Furthermore, he has allowed a .341 xwOBACON, which is slightly above average. He is doing this despite the 96 overall TJ Stuff+ and 49.3% zone rate, which is barely below average. 

His most impressive offering this year is not the changeup, which has the highest grade in his six-pitch arsenal (54). Rather, it's been the four-seamer, which has the second-best grade with a 49 mark. 

The former St. Louis Cardinal is throwing his four-seamer 32.6% of the time this year, his most utilized offering. It averages just 92.9 MPH, but it sports a decent iVB of 18.6 and a spin of 2,174 RPM. He's generating a 30.8% chase, a 31% whiff, and .355 xwOBACON with the four-seamer, and it's interesting to see how he gets to those rates, based on his four-seamer heatmap data this season via TJ Stats.

Against righties, Wacha has been efficient in locating the pitch up and away from right-handed hitters. This has helped him produce not just a 36.4% whiff rate but also a 40% chase (O-Swing%) and a .219 xwOBACON. He doesn't generate a ton of called strikes with the four-seamer against righties, but his CSW is still solid at 29.2%. 

Against lefties, he's been more in the middle of the strike zone. As a result, his xwOBCON is higher (.404), and his whiff (29%) and O-Swing (25%) rates are lower. Still, it's been an effective weapon against hitters from both sides of the plate. 

Here's an example of Wacha getting a nice rise on the four-seamer and hitting that up-and-away spot against Atlanta's Austin Riley, producing a foul tip strike. 

 

While the four-seamer has been his main weapon against righties, his changeup has been a nice complementary pitch with the four-seamer against lefties. Here's a look at Wacha's changeup heatmap, and notice the much higher usage against lefties, as well as better results.

Wacha throws his changeup 33.9% of the time against lefties, compared to just 6.2% against righties. His changeup is more up and away against lefties, a contrast to the low and inside location against righties. Still, the results have been better against lefties, as he is producing a 32.8% CSW, a 31% whiff, and 32.4% O-Swing% with the changeup. 

Here's an example of Wacha utilizing that changeup up and away to Munetaka Murakami of the White Sox, who whiffs badly, as he is expecting a four-seamer on an 0-2 count in that spot.

 

Wacha has always led with his four-seamer and changeup. However, in 2023 and 2024, he led with the changeup and followed it up with the four-seamer. The past two years, he's been more fastball-focused with the changeup as his secondary option to put batters away. That is clear in his pitch usage trend over his career, as shown in Baseball Savant's chart.

While some may be flummoxed by Wacha being so confident with a four-seamer that averages under 93 MPH, it seems to be working for the crafty righty so far this season.

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Can Wacha Keep Up These Solid Results?

I don't think Wacha is going to finish the season with an ERA under one. That's impossible, even for the best pitchers in the game. However, it's not out of the question to think that he can at least maintain his 3.04 FIP or 3.46 xERA over the course of the 2026 season. 

It will be interesting to see how his results fare over the season, especially when comparing his TJ Stuff+ data from this year to 2025. The results are very different, as shown below. However, the TJ Stuff+ marks for his pitches this season mirror closely what he produced a season ago. 

Last year, Wacha produced a 97 TJ Stuff+ overall, one point better than his mark this season. His changeup is three points worse this season, but his four-seamer is three points better, as well. Thus, it makes sense why his four-seamer has been more effective than his changeup in 2026.

A key to his success in 2026 will be his ability to maintain that four-seamer command. Yes, he's generating slightly better iVB and spin on the four-seamer this season. That said, the biggest difference for Wacha and his four-seamer is the location, especially against righties. Below is his 2025 four-seam heatmap.

The four-seamer had a good CSW against righties with a 29% mark. However, the whiff rate was much lower at 22.3%, and his O-Swing% was also paltry at 19.8%. Furthermore, his four-seamer got hit hard by righties, as illustrated by the .558 xwOBACON. That's 339 points worse than his mark this season. Then again, he threw 255 four-seamers last year compared to 24 this year, so it's not exactly a fair comparison.

Wacha has the stuff to produce another 3.30 to 3.60 ERA season, which would be more than serviceable for a pitcher expected to be the No. 3 starter in the rotation. His stuff profile and contact allowed illustrate that he can produce a season similar to what he's done from 2022 to 2025, when his ERA ranged from 3.22 to 3.86.

However, if the command can be maintained, and he can keep generating the whiff and chase on the four-seamer?

Well, if that happens, it wouldn't be surprising to see Wacha push for a spot in the All-Star Game in Philadelphia. 

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