Jesse Chavez: Is his Atlanta Braves uniform magic?

Atlanta Braves Country is Jesse Chavez Country, and we are just living in it. Over the past two seasons, Chavez has been exceptional in the regular season when in Atlanta, but well below average everywhere else.

If we strip out all the intangibles and just look at the math of it all, it is mind boggling. Let’s look at his 2022 season for example. During his 49.0 innings pitched over forty-two games between April 23rd and August 28^th for the Braves, he had a 3.31 ERA, with hitters slashing a .269/.321/.415. He also sported an very good 3.03 FIP with his xFIP still being very good as well at 3.15. His walks per nine innings was only 2.6, his K/BB rate was 4.1, and he had a decent 0.9 HR per nine innings.

But, when not with the Braves it was very different. In his limited time with the Cubs (5.2 innings over three games) Chavez’s numbers were terrible. Hitters slashed .318/.375/.545 with Chavez having a 6.35 ERA, 5.41 FIP, 4.42 xFIP, walks per nine innings was 3.2, K/BB rate was 1.5, and HR per nine innings was 1.6. This of course is a very small sample size, but his time with the Angels was not anything to write home about either.

We should point out that his May with the Braves was not good. Over 9.0 innings pitched (again, a small sample) he had a 6.00 ERA, 3.56 FIP and hitters slashing .368/.405/.579. But, as can be seen by his overall numbers with the Braves, he corrected course.

In his time with the Angels in 2022 (10.2 innings pitched over eleven games), hitters slashed .326/.380/.967, and his ERA was 7.59, FIP was 4.80, and xFIP was 4.03. His walks per nine innings was 3.4, K/BB walk was 2.5, and his HR per nine innings was the worst between all three teams at 1.7. Obviously he was a bit unlucky based on the gap between his xFIP and his ERA, plus hitters had a BABIP of .382 against him. Still, these numbers are ugly compared to the time on the Braves.

His second stint with the Braves in 2022, was not as good as the first with hitters slashing .222/.276/.444 in 14.2 innings, but overall his work for the Braves was far better than not with the team.

In the previous two season it was much of the same. In 2020 he had a rough year in Texas, followed by an excellent 2021 in Atlanta. With Texas, he had a limited 17.0 innings pitched in which he had an ERA of 6.88, FIP of 7.66, and xFIP of 5.57. Hitters hit .303/.364/.621 against him. He had a walk rate of 3.7 per nine innings and a K/BB rate of 1.9. Even if his ERA were to have had dropped to match his xFIP, it still would be considered a terrible performance.

As most probably know, 2021 was much different for Chavez. He was a key contributor for the World Series champions. In 33.2 innings pitched he had a 2.14 ERA, 2.01 FIP, and a 3.69 xFIP. Hitters slashed .192/.256/.267 against him and he did not give up a single HR. He walked 2.9 per nine innings and had an excellent 9.6 K/BB rate.

Was it just luck or coincidence that Chavez performed much better as a Brave?

By just looking at his xFIP, we can see that he was most likely was truly pitching better. But, we can look at his underlying metrics and really see how much changed with the changing of his uniforms.

Starting with the 2022 season, we can look at his xwOBA by month to get a good idea of if his surface numbers were more coincidence or on par with what they would be over a longer sample size.

As can be seen, in the month of May he really was pitching bad overall with an xwOBA of .426. For reference, the league average xwOBA in 2022 was .339. In other words, it was not bad luck for Chavez in May. On the same note, we see once he got in the groove in June, he really was pitching well in a sense that he was not just getting lucky with an excellent .235 xwOBA, followed by a .298 in July. Then we can see in August when he was shipped off to the Angels, he was back to a .326. Not terrible, but much worse than how he was performing in Atlanta.

Specifically what sticks out in his really good two month stretch between June and July when he pitched for the Braves is that in June his average EV was 87.0 MPH with a launch angle of seven degrees. In July his EV against was only 84.9 with a launch angle of nine degrees. In all other months he had an EV of 90.6 or higher. In April, May, and September hitters has much more optimal launch angles of twenty-one, sixteen, and sixteen degrees respectively.

The interesting part is that it was not any single pitch that he started performing well or worse as time went on. If we look at the months as they go by we can see that the different pitches xwOBA seems to rise and fall together, suggesting that it may possibly be the environment.

The same seems to be true from 2019-2020 when he was with Texas (albeit, a small sample in 2020), and when he moved to Atlanta in 2021. His xwOBA in Texas was .339 in 2019 when he threw 1306 pitches, and then it was .393 in 2020 (305 pitches). Once he moved to Atlanta in 2021, his xwOBA against him dropped way down to .271 in 528 pitches. The best of his career for a season.

Is there really magic in the air when Jesse Chavez pitches in Atlanta? Is he just more comfortable? Whatever it is, the number back up that he pitches better than, and it goes much deeper than just surface numbers or luck.