Predicting the Diamondbacks' Backup Catcher Decision

The Arizona Diamondbacks have a Gold Glove winning catcher in Gabriel Moreno, and at the young age of 25 his already-capable bat has plenty of room to grow. It's hard to overstate how important he is to the team and their chances of winning.

But Moreno has not been especially durable the last two years, starting just 94 and 83 games in 2023 and 2024. Ideally the D-backs would like him to start 110-115 games behind the plate. While he came to camp this year with a clearly more toned body, the team needs to have strong catching depth behind him. The two candidates are Jose Herrera and Adrian Del Castillo.

Herrera is a light-hitting catcher with a .207 career batting average and 51 OPS+ in 358 PA. Despite being a switch hitter, there has been no discernible advantage from either side of the plate. He has a .529 OPS against right-handers and .561 against lefties. So far this spring he's batting .300 (6 for 20), with two RBI, one walk, and just three strikeouts.

The area where Herrera has shined brightest is drawing high marks for handling pitchers as they enjoy throwing to him. Herrera also has a career 24.4% caught stealing rate, compared to league average 21.1%. That rate plummeted in 2024, however, as he caught just 9.7% of would-be base stealers.

Perhaps the biggest advantage the 28-year-old Herrera has in this competition is the fact that he's out of minor league options. In years past that worked against him at times, as other veteran backup options could not be optioned to the minor leagues. But as Mike Hazen explained earlier in spring, that door has now swung back the other way in Herrera's favor.

Del Castillo broke out in Triple-A Reno in 2024, batting .312/.399/.603 with 26 homers in just 413 Pacific Coast League at-bats. The left-hand batter's hard-hit metrics in that league were the stuff to drool over.

He then burst on the scene for two weeks in August when first called up, batting .361 with three homers and 14 RBI in his first 10 games. That also included a BABIP over .500 and 14 strikeouts. The swing-and-miss tendency and batted ball luck eventually caught up to him a bit, as he hit went 12-for-44, .278 with just one homer and a .728 OPS over his next 15 games, including 14 more strikeouts.

It wasn't the expected regression to the mean for his batting numbers that caused him to be sent back to Reno instead of Herrera when Moreno came off the injured list. Del Castillo's defense was clearly not quite ready, especially the throwing. He caught just two of 29 base stealers, 6.9%.

Del Castillo has worked hard over the offseason and this spring training to make improvements with his footwork, release, and arm strength. So hard in fact that he came down with a sore arm and missed a week of games behind the plate.

But soon after returning to catching duties he flashed improvements he's made, throwing out a runner in Las Vegas against the A's, and just missing getting a second caught stealing against the aggressive Athletics. Visually it's clear that the work is paying off.

Ironically, it's the bat that has let him down this spring, as he's batting just three for 25, .125, with a whopping 12 strikeouts and zero walks.

While Torey Lovullo frequently explains how results such as traditional batting numbers or pitcher ERA have little if anything to do with their spring evaluations, Del Castillo probably needed to tear the cover off the ball, along with showing the improvements to his throwing, to have a shot at superceding Herrera to start the season.

Prediction

Our prediction is that Herrera will capture the opening day roster spot for backup catcher. The simple fact that Herrera is out of options is likely to be the deciding factor here. The D-backs have also usually put the emphasis on defense when it comes to backup catcher decisions.

Del Castillo will catch more than half the games in Reno to start the year and continue to work on the improvements to his defense, while also looking to close up the hole in his swing that leads to so many strikeouts. It's our view that long-term Del Castillo has the much higher upside, but the team can afford to let him hone his skills just a little while longer.

If the offense is struggling early in the year, it might not be long before Del Castillo is called back up to give a jolt as he did last year. And of course the specter of Moreno missing time again always looms.

It should be noted there is one other catcher on the 40-man roster, 28-year-old René Pinto. He too is out of options however, having been waived by both the Tampa Bay Rays and then the Orioles during this offseason. Claimed by the D-backs on January 10, there is little if any chance to steal the role. He would need to clear waivers for the D-backs to be able to send him to Triple-A Reno.

He's had a good spring at the plate, batting 4-for-13, .308 with two doubles and two RBI. He looks solid defensively. But in 82 major league games for the Rays over the last three years he's caught just five of 55 base stealers in his career, 9.1%.

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