clock menu more-arrow no yes mobile

Filed under:

2023 Diamondbacks Reviews: #34 Miguel Castro

The puzzling case of Miguel Castro

Texas Rangers v. Arizona Diamondbacks Photo by Daniel Shirey/MLB Photos via Getty Images
  • Rating: 4.51
Look at that normal distribution!
  • 2023 stats: 75 G, 64.2 IP, 4.31 ERA, 4.31 FIP, 1.175 WHIP, 2.40 K/BB, 101 ERA+, 0.4 bWAR
  • Date of birth: December 24, 1994 (28 years old)
  • 2023 Earnings: $3,500,000
  • 2024 status: Signed through 2024


When Mike Hazen signed Miguel Castro last December, it was met with understanding and approval but little fanfare. This made sense since the 28-year old was coming off a solid season with the Yankees (pitching to a 4.03 ERA across 34 games), but he had also suffered from a shoulder strain that scared other suitors off. Thus, Hazen rolled the dice on the hard-throwing righty and built in plenty of incentives to the contract to insulate the club in case the injury reemerged or there was significant regression. Luckily for the D-Backs, Castro was one of the more consistent relievers out of a bullpen that saw plenty of change over the course of the season. Unfortunately, that consistency came with a price as the Dominican native once again showed why he’s had such promise in his nearly 10 years in the majors, but also why he’s failed to stick with any franchise for very long.

Since debuting as a 20-year old for the Blue Jays back in 2015, scouts and analysts alike have been enamored with Castro and for good reason. His 6’7” frame gives him the kind of length that only accentuates the velocity he brings on his sinker, which averaged at 96.8 for 2023, while pairing it with a slider that accumulated a measly .171 BAA. Frustratingly, Castro’s size has made him prone to wildness and a lack of command, the combination of which has kept him out of the upper echelons of relievers around the league. Through his career, there’s only been one full season in which he managed to post a walk rate below 10% and that was during an abbreviated stop in Colorado with just 14.2 IP across 19 games. He has also been somewhat homer prone with above-average home run rates in six of his major league seasons. Paradoxically, Castro profiles as a ground ball pitcher in his career to this point, which further highlights the lack of control the veteran can sometimes exhibit.

2023 Review

Putting these pieces together, Castro comes across as the perfect low-risk, high-reward type of signing that has come to typify the Hazen front office. For the most part, 2023 brought more of the reward than might have been expected during his signing. Through the first two months of the season, Castro was arguably the D-Backs’ best reliever. He posted a 2.22 ERA in 24.1 IP across the first 26 games and seemed to have resolved both his home run and walk issues with just one and eight allowed respectively to that point. It was enough of an emergence to prompt articles like this one that took a deep dive into Castro’s usage with Brent Strom and Torey Lovullo. According to Strom, Castro was overused in the past and agreed to take the ball even when, “...he wasn’t feeling right,” which led to downturns in his performance.

While we can’t directly test the injury aspect, the numbers somewhat bear out Strom’s hypothesis on exhaustion affecting his performance. In the monthly breakdown of Castro’s 2023, he seemed to tire as the season progressed - especially in August when he had his worst month of the season. During the month of August, his ERA ballooned from a reasonable 3.95 to an unsightly 5.20 in 15 games and just 10.1 IP. In his defense, much of that ugliness came from back-to-back disastrous outings against the Rockies and then the Padres when he allowed 8 total runs on just 1.1 IP. There is further reason to dampen Strom’s hypothesis as Castro ended the regular season on an 11-inning scoreless streak at a critical juncture of the season that helped lead the team into an unlikely playoff berth. And we all know where that berth eventually landed.

Unfortunately, the D-Backs got more of the bad Castro than the good one in the playoffs, including allowing the walk-off homer to close game one of the World Series and culminating in an uninspiring appearance in game four when he allowed three of the Rangers’ 11 total runs. Despite leaving an ugly taste in fans’ mouths from a disappointing playoff and World Series run, Castro projects out to be an important cog in the D-Backs’ 2024 bullpen. He particularly shone in a set-up role during 2023 when he posted a 2.87 ERA and a 0.986 WHIP while pitching in the seventh inning. Conversely, those numbers inflate to 4.91 and 1.16 respectively when Castro pitched in the ninth inning. Luckily, with Paul Sewald returning for 2024, Castro shouldn’t be appearing in the ninth inning or save situations next season and instead continue to excel as a set-up man moving forward. I for one am excited to see what he can accomplish next year.