Adrian Del Castillo had an excellent cup of coffee with the Arizona Diamondbacks in 2024. He was called up to fill in for an injured Gabriel Moreno and in 25 games he slashed .313/.368/.525. He hit 4 home runs in 80 plate appearances and registered a 146 OPS+. In almost every way it was a highly successful debut for Del Castillo. He is also an interesting case as to why it is so difficult to evaluate minor league catchers for fantasy.

Del Castillo was drafted by the Diamondbacks in the 2^nd round of the 2021 amateur draft. He was considered a first-round prospect heading into the season but he did not hit well during the NCAA season. He continued to struggle with the bat in his professional debut, slashing .199/.287/.346 in 77 games at High-A Hillsboro. For a player who was age-appropriate for the league and coming from a high-major college program, his missing offensive production was concerning. Del Castillo started 2023 at Double-A Amarillo, and he seemed to figure some things out. He produced a .891 OPS and showed massive improvement in his slugging percentage.

Del Castillo started the 2024 season at Triple-A Reno. Reno is a favorable hitting environment, but even in that context his season was terrific. In 105 games he hit 26 home runs, 36 doubles, and produced a .312/.399/.603 triple slash line. Del Castillo struck out in only 17% of his plate appearances and walked in 11.6%. His underlying numbers support his breakout, as he produced a 90^th percentile exit velocity of 105.3 miles per hour and a maximum EV of 111 mph. He made contact on pitches in the zone at an 83.5% clip and only chased 25.7% of the time. Del Castillo’s hard-hit percentage, launch angle, and barrel percentage were all elite.

If it were just down to this side of the equation, Del Castillo is an easy buy now and must have on any dynasty team. Unfortunately, it isn’t. He has a lot of work to do to get to be an average defensive player. More than any other position it seems that Major League teams value defensive contributions out of catchers over offense. It makes sense. Between pitch-calling, framing pitches, blocking, and throwing out base stealers, catcher is the most important defensive position on the field. This is where Del Castillo has problems.

In just 24 games at catcher, the Fielding Bible estimates Del Castillo was worth -2 runs. His “Catcher ERA” was worth -1 run, and he cost -2 runs from stolen bases. Statcast valued his pitch framing as worth -1 run as well. His arm grades as below average, and he allowed 27 steals in 29 attempts.

None of that is going to fly unless he’s a Mike Piazza/Hall of Fame level bat. I think it’s safe to say that he’s not on that level. All of those are skills that can improve, aside from arm strength. However, all his defensive problems that I just cited are problems that have existed since his days at Miami. After 4 years of professional instruction, I am skeptical that he can become even a below-average defender. Del Castillo’s future is tied to his bat. but the good news is it will be fine at the Major League level. Can he hit enough to slide to first base or DH? At this point I think this might be his most viable path to a spot on a Major League roster.

Del Castillo is also the type of catcher that would benefit greatly from an automated ball/strike system or a ball/strike challenge system. Major League Baseball is testing the challenge system this spring. MLB may implement it in the near future. A deeper analysis of what a rule change might mean for catchers deserves its own article. Removing framing from the equation would certainly be helpful for catchers with a bat-only profile. Del Castillo has other defensive warts, specifically his arm strength and throwing mechanics that need ironed out. Right now, his bat might be enough to keep him as a catcher-eligible player. But given how highly catcher defense is valued right now in the Majors, 20 appearances, and therefore catcher eligibility in most fantasy formats, might end up a stretch for Del Castillo.

(Brandon Ring)