Arizona Diamondbacks shortstop Geraldo Perdomo's broke out in the 2025 season, emerging as one of the top offensive threats in an already-potent batting order. He wasn't satisfied with the season that led him to a fourth-place MVP vote a year ago, however.

Following the conclusion of that 2025 regular season campaign, Perdomo made it very clear that he wanted to improve drastically in one specific area: his defense at short.

"I feel like it's been a great season, but on the glove side for me it's been my worst season, even if the numbers say it's positive," Perdomo said at 2025's end.

"I feel disappointed with the way I've been performing on defense, because that's not me. ... "I need to put a little bit more effort this offseason, work a little bit harder and perform the way I know I can perform on defense."

He did exactly that in the 2026 season, and then some.

Geraldo Perdomo made big defensive strides for Diamondbacks in 20226

First, let's take a look at Perdomo's defense in 2025.

Over 161 games at shortstop, Perdomo was worth +3 Defensive Runs Saved, +3 Fielding Run Value and +5 Outs Above Average.

It looked, on the surface, like a positive season defensively. But he also committed 18 errors — by far his most ever in a season. Though the advanced metrics suggest he was a strong fielder overall, the .971 fielding percentage and uncharacteristic collection of mistakes were worthy of self-critique.

2026 was a different story.

Perdomo played 157 games. He cut his errors by more than 50%, committing eight. He posted +8 Defensive Runs Saved, the second-most of his career.

According to Baseball Savant, he collected an astounding +13 Fielding Run Value and +16 Outs Above Average. Not only are those numbers both in the top 5% of MLB, the wholesale defensive resume was enough to earn him a Gold Glove nomination at season's end.

As a result, Perdomo was the second most valuable player on the team by average WAR. He was worth just over 5.0 WAR, averaged between FanGraphs and Baseball-Reference.

To get the offensive issues out of the way, Perdomo slashed .262/.370/.377 for a .747 OPS and nine homers — not exactly a poor season from your franchise shortstop.

His biggest area of regression came situationally; he fell from a .331 2025 average with runners in scoring position to .186 in 2026, while losing a chunk of his slug.

But at shortstop, the 27-year-old kept his promise. He played the strongest, most reliable defense of his career, and did so very consistently.