Inspiration.
Before this season started, I asked, “Will Perdomo regress or continue his breakout?”
Nearly two months into the season, let’s look at what happened to his batting. Two notes follow:
- Before reading onward, please note that batting is just one of many ways that Perdomo contributes to team wins.
- Before reading onward, please note that I exercised restraint in my tendency to include tables of data (which could have been overwhelming). Data from Baseball Savant, FanGraphs, and Baseball Reference.
Batting Metrics.
Last season, he experienced a batting breakout. As mentioned in the article, his foundational batting strengths included squared up per swing and launch angle sweet spot. A third foundational batting metric is bat speed. Let’s look at those three foundational metrics, and more metrics.
Improved Metrics. Compared to his
breakout season, this season in games through 21 May, his squared up per swing with contact improved from 36% to 40%. Other improved metrics included hard hit percentage (31.9% to 34.7% per Baseball Savant) and line drive percentage (23.3% to 24.8% per FanGraphs).
In summary, this season some aspects of Perdomo’s batting are better than his breakout season.
Regressed Metrics. Traditional metrics, such as OBP, SLG, and OPS regressed. Perdomo’s OPS+ fell from 137 to 96.
Last season, Perdomo’s foundational bat speed improved albeit it remained below league average. This season, his average bat speed dropped from 68.3 MPH to 66.3 MPH. Please note that this season, his two homers had bat speeds of 69.2 and 70.4 MPH, which are below the 72 MPH league average. Perhaps for Perdomo, other factors such as launch angle are very important.
Last season, Perdomo’s foundational launch angle sweet spot percentage was above-average. This season, it dropped from 15.5% to 12.2%.
In summary, several metrics point to regression from last season’s breakout. Perhaps the most important two metrics were bat speed and launch angle sweet spot. When those improve, I’m confident Perdomo will continue his breakout.
What is the story for the rest of the season?
Three viewpoints that are optimistic for the rest of the season follow.
Viewpoint 1. Perdomo was on an unlucky batting streak; he will soon return to last season’s level of performance. The biggest signpost was BABIP. His BABIP fell from .317 in 2024, to .303 in 2025, to .244 this season through 21 May. Experience has shown that often when BABIP changes by a lot, the change will not be sustained. Looking at more detail, this season through 21 May, his BABIP for breaking pitches fell from .338 to .150. I’m confident that was an anomaly that will not continue. BABIP for breaking pitches will likely double for the rest of the season.
In summary, Perdomo started the season on an unlucky streak, and it will not continue.
Viewpoint 2. In February 2025, Perdomo said he focuses on hitting line drives. Perhaps that focus is a key to his breakout. That metric shows an overall improvement from last season’s level (20.0% to 28.4%). With a caveat that line drive rates on sliders (13.3%) and changeups (18.5%) need to improve, I’m confident that his higher rate of line drives will eventually increase the rate at which he hits home runs because of his increase in hard hit percentage.
“I know I had a little bit of pop. I don’t try to hit for homers. I just try to hit more line drives. If it happens sometimes on accident, I take it. I think it’s going to come with time.” — Geraldo Perdomo, February 2025
In summary, Perdomo’s improved line drive rate (beyond his breakout season) will eventually improve his overall batting statistics.
Viewpoint 3. This season, comparing May (games through 21 May) to March/April, he improved his bat speed (65.6 to 67 MPH) and increased his average launch angle (10 to 16 degrees). Those two foundational metrics were worse this season, and in May Perdomo significantly improved them. In combination with his improved squared up per swing with contact, he is on the path to continue his breakout.
Recently, launch angle seems more important than bat speed (which is good news). A focused data excursion (manually gathered each data point) focused on 1-21 May, looked at balls in play with launch angles between 10 and 35 degrees. The percentage of hits was perhaps only weakly correlated with bat speed. Results follow:
- 66.7% hits, bat speed less than Perdomo’s average.
- 28.6% hits, bat speed above Perdomo’s average, but less than 69 MPH.
- 75.0% hits, bat speed of at least 69 MPH (League average was 72 MPH).
In summary, his improved foundational batting metrics will eventually improve his overall batting statistics.
Summary.
Tradional batting metrics seemed to show that this season Perdomo regressed from last season’s breakout. Two foundational batting metrics (bat speed and launch angle sweet spot percentage) regressed. However, some metrics (such as percentages for squared up, hard hit, and line drives) show an improvement beyond his breakout season.
Three viewpoints that are optimistic for the rest of the season follow.
- Perdomo was unlucky. His BABIP dropped and will bounce back.
- Hitting line drives is a key to Perdomo’s success. His improved line drive rate (beyond his breakout season) will eventually improve his overall batting statistics.
- In May (compared to March/April) he improved his bat speed and launch angle sweet spot percentage. His three improved foundational batting metrics (squared up, bat speed, and launch angle sweet spot) will eventually improve his overall batting statistics.
