Adrian Del Castillo Emerging as a Backstop for the Diamondbacks

Adrian Del Castillo has had a streaky start to his MLB career. Is he here to stay?

Aug 19, 2024; Miami, Florida, USA; Arizona Diamondbacks catcher Adrian Del Castillo (25) celebrates with teammates after hitting a grand slam against the Miami Marlins during the third inning at loanDepot Park. Mandatory Credit: Sam Navarro-Imagn Images / Sam Navarro-Imagn Images

The Arizona Diamondbacks are in the midst of a playoff push, sitting atop the NL Wild Card picture. The team is on the verge of clinching a playoff berth in consecutive seasons for just the second time in franchise history, and its offense has been a big part of the club's historic run. The lineup has slashed .263/.336/.442 for a 115 wRC+, the highest mark in franchise history by far, per Fangraphs.

Arizona's management team has put together a dominant lineup prepared to handle the league's best this season. Veterans like Ketel Marte, Christian Walker, and Joc Pederson have led the way. But several spots around the diamond are secured by up-and-comers like '23 first-time NL All-Stars Corbin Carroll and Geraldo Perdomo, as well as Jake McCarthy.

Perhaps there isn't a position in better shape for the long term than catcher. Adrian Del Castillo and Jose Herrera have been holding down the fort behind the plate, but that setup will change once Gabriel Moreno returns from the injured list. That could happen as early as the upcoming series at Colorado, as reported by Jack Sommers on Friday.

Arizona's depth has been tested this season, as most positions have been impacted by injuries at least once, and catcher has been one of them. Moreno has missed over a month with a groin injury.  He continued to show the makings of an all-around catcher before getting injured in early August. Over his last 24 games, Moreno slashed .333/.409/.481 for a 149 wRC+, the third-highest among 19 catchers (min. 80 PA's) in that span, per Fangraphs.

Del Castillo had big shoes to fill when he was called up for his MLB debut just over a month ago, and he didn't waste any time to make that happen, as he caught fire for his first 14 games. He slashed a whopping .354/.426/.583 for a 1.009 OPS in that span.

He also became the second player in Diamondbacks history to record a walk-off as their first-ever home run in the show, and he did it in just his second MLB game. His memorable run to kick off his MLB career equated to a 180 wRC+ (80% above league average), which was in the top ten percent (seventeenth-highest) of 241 batters (min. 50 PA's).

Del Castillo's start to his MLB career was surely impressive, but luck was on his side as well. Del Castillo sported an unsustainable .500 BABIP in that span. The league average on balls in plays is .290.

Since then, Del Castillo's BABIP has regressed all the way down to .267, and his overall production has gone down with it. Over his last nine games he's batting .185 with a .584 OPS.

Not all of Del Castillo's decline from his sensational start has been a result of batted-ball luck, as Manager Torey Lovullo said, "He got off to a very fast start and had some big homers for us, and the league has made a little bit of an adjustment to him."

That said, there’s still a lot of optimism surrounding his offensive output based on some of the stats he’s consistently put up in the minors, particularly his batted-ball contact.

Since his first full season in the minors in 2022, his 0.89 GB/FB (groundball-to-flyball ratio) ranks in the bottom 20 percent of 442 minor leaguers, and his 24.9% line-drive rate ranks in the top 15 percent (24th) in the minors (min.1000 PA’s and currently younger than 26), per Fangraphs.

His penchant for hitting the ball in the air in the minors has clearly translated well to the big-league level, with four home runs so far and an above-average 12.8% Barrel rate and 38.3% Sweet Spot rate. He’s even batted to a lower 0.76 GB/FB with an above-average 19.6% line-drive rate in nearly 50 batted-ball events so far.

Del Castillo hits the ball hard, but he struggles with making contact. He's struck out 34.1% of the time 28 strikeouts in 82 PA) and posted a low 76% In-Zone Contact rate, per Baseball Savant. His up-and-down start to his career has still amounted to above-average production, hitting to a 137 OPS+ (37% above average), per Baseball Reference.

Adrian Del Castillo's bat has picked up where Moreno left off, though on the other side of the ball, it's been a different story. Runners have taken advantage of Moreno's absence, as they've successfully stolen 26 times against Del Castillo in just 167 innings behind the plate.

He has thrown out just one baserunner for a 96.3% stolen-base success rate, the worst rate among 62 MLB catchers (min. 25 stolen-base attempts). Del Castillo's issues behind the plate are likely attributed to his slow pop time at 2.03 seconds, which ranks in the worst ten percent in baseball, per Baseball Savant. Manager Torey Lovullo is aware of the issue, saying that "the throwing is still a work in progress."

Going from a quick arm in Moreno behind the plate to Del Castillo has presented its challenges for pitchers when trying to control the run game, as Lovullo said that "pitchers are very aware when Gabby is back there."

Lovullo, however, acknowledged that Del Castillo is trying to narrow the gap between his glove and Moreno's. "He does a great job of getting the information, memorizing it or using it when he needs to. I think he is going to develop more of a feel for when things need to be changed and some adjustments that needed to be made on the fly," Lovullo noted. "He's been working hard to make it happen."

Once Moreno returns, one of Herrera, 27, or Del Castillo will likely get sent down to Triple-A. It's not yet clear which player the team will hold on to for the stretch run. Del Castillo's bat is far superior to Herrera's, while the latter is the preferred catcher for Zac Gallen and simply has more experience with the pitching staff.

Stay tuned to Arizona Diamondbacks ON SI for further updates on the status of these two players in the coming days.