Inspiration.
In the AZ Snake Pit’s pre-season wagers, I risked embarrassment. Three of my wagers depend on Geraldo Perdomo.
- OVER Perdomo .275 BA.
- OVER Perdomo 17.5 homers.
- OVER Diamondbacks 80.5 wins.
But what if Perdomo’s performance regresses from last season’s highs? That could tip the Diamondbacks below 81 wins. And three of my five wagers would be losers. Let’s look at what will likely happen.
Was his 2025 breakout real?
One stat was so extraordinary, that his breakout was certainly real instead of a technical fluke. That stat was Wins Above Replacement (WAR).
Jim McLennan wrote that Geraldo Perdomo Should Have
Been the MVP Runner Up. What impressed me most was the WAR table. It had three data columns: bWAR, fWAR, and the average of the two. All three columns showed Perdomo as the clear runner up to Ohtani.
Will he regress?
The argument for regression is well articulated in the following quote. “After hitting just 14 home runs in 1,420 plate appearances during his first four seasons in the big leagues, Perdomo’s home run total [20] was the most unexpected part of his elite 2025 campaign. However, his average exit velocity (16th percentile), hard-hit rate (11th percentile) and bat speed (7th percentile) raise some serious questions about the sustainability of his power surge. His defense and on-base ability still give him a 3-WAR floor, but significant regression seems likely.” — Joel Reuter, Feb 2026
My view is that it’s not valid to predict regression by looking at Perdomo’s batting weaknesses, without also looking at Perdomo’s batting strengths that resulted in his “elite 2025 campaign.” Nevertheless, regression could happen.
I looked at eight projections for Perdomo homers in 2026. Each projection had its own PAs and homers. It’s a big assumption, but assuming the same PAs as last season, and no change in the homers per PA of the projections, then with 720 PAs, the projections ranged from 12.2 to 15.7 homers. My wager of Perdomo hitting 18 or more homers is equivalent to roughly 15% more homers than the most optimistic projection. However, my wager was based on more than just raw optimism. Read on!
How can I understand his 2025 breakout in context of his batting weaknesses?
The following graph (courtesy of Baseball Savant) shows his below-average bat speed (68.3) and his above-average squared up per swing (32.3%). Perdomo is circled in red and a red arrow points to him.
Also, Perdomo was above-average in launch angle sweet spot percentage (36.2%). With his below average bat speed and his below average hard-hit percentage (31.9%), his 20 homers were exactly in the middle of the 145 qualified batters. That shatters the preconception that high bat speed and a high percentage of hard hits are ‘the only way’ to hit homers.
Another shattered idea was that batters who hit homers were focused on hitting homers. Geraldo Perdomo said the following about his focus: “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
Another important idea is that Perdomo has two types of swings; homer swings and non-homer swings; each with its own swing speed.
“…Perdomo dramatically increased his swing speed on home run swings. Each of the first 2 seasons, we see that the split in swing speed from home run to non-home run was right around 2-2.5 MPH. This season, those splits grew to 4-5 MPH. How rare is that? The league average swing speed split between homers and non-homers in 2025 was 2.8, basically right where Perdomo has been for the last 2 seasons. In 2025, his overall split of 4.3 MPH was 12th-highest out of over 140 qualified hitters in MLB.” — 1AZfan1, February 2026
The graph shows that in 2025, Caleb Durbin was most like Perdomo in bat speed and squared up per swing. It was Durbin’s rookie season. Remarkably he earned 2.8 WAR. Durbin and Perdomo were born exactly 4 months apart. It will be interesting to compare them at the end of this season.
In 2026, will his breakout continue?
His batting strengths have existed since 2022, when he was a rookie in the Majors. In December of 2023, my player review included the following table that compared Perdomo to the other Diamondbacks batters.
“Thus the combination of bat control along with a faster swing is producing a marked increase in the quality of contact, making his [Perdomo’s] above average batting line appear much more sustainable than in the past.” —Jack Sommers, April 2025
In 2023 and 2024, one stat (created by 1AZfan1) showed Geraldo Perdomo was top-two in the Majors. That stat is Peskiness; a combination of many pitches per PA, few swings outside the strike zone, and few whiffs. In short, pitchers see him as the most Pesky batter in the Majors. My view is that the most important part of Peskiness is that he gets more pitches per PA, which gives pitchers more chances to make a mistake pitch that allows Perdomo to hit a homer.
In 2025, what happened? Is Geraldo Perdomo Still Pesky? Yes, he is still number one!
Three consecutive years as the best in the Majors shows consistency that argues that his breakout will continue.
Perdomo has gone beyond Pesky. He improved his batting. Details are in the following quote.
“Perdomo has gotten bigger and stronger. He’s changed his mechanics from both sides of the plate. He’s somehow chasing and whiffing even less than he did last season, and he’s somehow doing so while lifting the ball more, swinging a bit harder, and hitting the ball a bit harder.” — Davy Andrews, September 2025
All things considered, I’m confident his breakout will continue.
Two Very Positive Projections for 2026.
In his Positional Power Ranking for Shortstop, Dan Szymborski ranked the Diamondbacks as number 6. “He [Perdomo] might even still be underrated; I’m surprised at how little attention was given nationally to his elite performance in 2025.” — Dan Szymborski, March 2026
“It wouldn’t surprise me if … Geraldo Perdomo becomes a top-three shortstop in baseball this year. … Either way, Perdomo’s skill set — more walks than strikeouts, power, speed, glove — puts him in a position to lock up the spot in 2026.“— Jeff Passan, Mar 13, 2026
Summary.
His 2025 breakout was real.
Perdomo has batting weaknesses that could lead to regression. But it’s not valid to look at his batting weaknesses without also considering his batting strengths that caused his breakout.
Perdomo’s batting strengths include squared up per swing and launch angle sweet spot percentage.
My wager of Perdomo hitting 18 or more homers is equivalent (with 720 PAs) to roughly 15% more homers than the most optimistic projection.
Thoughtful ideas included:
- High bat speed and a high percentage of hard hits are not the only way to hit homers.
- With a focus on hitting line drives, Perdomo hit 20 homers.
- Perdomo has two types of swings; homer swings and non-homer swings; each with its own swing speed.
His breakout will likely continue.
- His batting strengths have existed since 2022, when he was still a rookie in the Majors.
- Bat control and a faster swing increased the sustainability of his breakout.
- For three years, pitchers have found Geraldo Perdomo the most Pesky batter in the Majors because of his many pitches per PA, his few swings outside the strike zone, and his few whiffs.
- Beyond being Pesky, last season Perdomo improved his batting with more strength, better mechanics, more lift of the baseball, swinging a bit faster, and hitting the baseball a bit harder.
Two writers have projected that this season Perdomo will be the third and sixth best shortstop in the Majors.
I’m confident that Perdomo’s performance will exceed .275 BA and 17.5 homers, helping the Diamondbacks win more than 81 games.
