Atlanta Braves: Breakdown of Joe Jiménez

When the Atlanta Braves traded Justyn-Henry Malloy and Jake Higginbotham to the Tigers for Joe Jiménez back in December, there was some head scratching going on amongst some fans across social media.

It could have been that since Joe Jiménez had played for a bad team in the Tigers, he was not well known to fans in Braves Country. It could also have been due to the fact that the Braves just traded arguably their top position player prospect at the time for one year of a relief pitcher.

The reality is that Malloy was a top prospect in a farm system that has already been gutted as we see with not a single Atlanta Brave on the top 100 prospect list from MLB.com, and Joe Jiménez was a very good pitcher in 2022.

Joe Jiménez had a breakout year in 2022

If we look at his surface numbers, we can see that Joe Jiménez had easily his best year. His ERA of 3.49, FIP of 2.00, WHIP of 1.094, HRs per nine innings of 0.6, walks per nine innings of 2.1 and strikeout to walk ratio of 5.92 were all career bests by a decent margin. He also pitched 56.2 innings over 62 appearances.

Relievers can be very volatile when it comes to surface numbers because their sample sizes per season are much smaller than a starting pitcher. However, this was a full season of work and not a small cameo appearance for Joe Jiménez.

The real question is, do the peripherals back up his surface numbers?

In a nutshell, it can be said that his peripherals match his success of 2022. Joe Jiménez’s Statcast page is electric.

In 2022, his xERA was best 15.0 percent of the league, his xBA was best 26.0 percent, xSLG best 26.0 percent, strikeout rate best 5.0 percent, walk rate best 21.0 percent, whiff rate best 18.0 percent, and chase rate best 16.0 percent.

We saw flashes of this success in 2021 when his xBA was best 1.0 percent of the league, but he had major issues with walks being in the bottom 1.0 percent of the league. He corrected those issues in a major way and he reaped the benefits in 2022. In 2021, he had a career worst 6.9 walks per nine innings. In 2022 it dropped to a career best 2.1.

In theory, based on his peripherals, if Jiménez were to pitch like he did last year, he would still have a successful season again. Now, the environment will be different this year with the pitch clock and limited shift, but the environment has changed for everyone.

What was the key to Jiménez’s success?

We already mentioned the drop off in walk rate, which would help any pitcher. He also had a career high strikeout rate in 2022 at 33.3 percent. More specifically than the walk and strikeout rates is the use of his slider.

His xwOBA against his slider was a career low .189, which was well below the league average of .269. His xwOBA in 2021 was a respectable .240, but was still much higher than his exceptional mark in 2022.

His whiff percentages against the slider were very similar in both seasons. It was 43.0 percent in 2021 and 42.4 in 2022. His put away percentage did have an uptick of 3.0 percent, so that did play a role in his strikeouts going up. However, that is not enough for the massive drop-off in xwOBA against the pitch. So, if it was not solely swings and misses that helped this massive drop off in xwOBA, what did change? Primarily it was launch angle and exit velocity against.

In 2021 the launch angle against his slider was seventeen degrees, and in 2022 it dropped down to ten. The average exit velocity against his slider in 2021 was 86.8 MPH. In 2022 it dropped to 83.7.

What appears to have greatly helped these metrics was that he was able to get a lot more vertical movement on the pitch while sacrificing horizontal movement.

As can be seen, his vertical movement on his slider was a career high. This led to hitters not being able to hit the pitch as hard or at more optimal levels. This also contributed to his overall solid contact percentage of 2.8 percent being well below his career average of 6.7. For reference, the league average soft contact rate since 2017 is 5.7 percent. The intriguing part is that he virtually abandoned horizontal movement.

With the change of movement patterns it appears he has more control over the slider as well. His in the zone percentage on the pitch jumped from 38.9 percent in 2021 to 42.9 percent in 2022.

We talked about the massive drop off in xwOBA against his slider, but for those who like more traditional stats to help wrap your mind around how much his slider improved, the batting average against the pitch in 2021 was .217. In 2022 it was a measly .187. Even more impressive than that was the drop off in slugging. In 2021 the slugging percentage against his slider was .417. In 2022 it dropped all the way down to .227.

Now, his XSTATS tell a different story. It shows that he actually got a bit unlucky with his slider in 2021 with his xBA being .157 and xSLG being .266. However, his overall xwOBA still had a massive drop from 2021 to 2022.

It is no wonder that Jiménez is using this pitch at 30.8 percent of the time. What will be interesting to see in 2023 is the trend of his pitches. His usage of his slider stayed about the same from 2021 to 2022, but his fastball usage jumped from 54.0 percent to 63.7, and his changeup dropped from 13.0 to 5.4. If anything else, it points to how well his slider is doing that with hitters having less pitches to guess on, they had less success hitting his slider well.

The great thing for the Atlanta Braves is the fact that Jiménez wasn’t even picked up to be a high leverage arm. He would potentially be one of the best relievers on most teams, yet on the Braves he will most likely be a 6^th or 7^th inning guy.

Here’s to hoping for sustained success for Jiménez and that his change in his slider continues to be the x-factor.