Marlins prospect José Castro set a Dominican Summer League single-season record with 16 home runs, but his favorite swing of the year wasn’t one of those.
That honor goes to Castro’s walk-off homer in an intrasquad game, which secured bragging rights in a competitive setting the organization views as a fun and effective way to develop its players.
“It was a very exciting moment for me,” Castro said via interpreter Luis Dorante Jr. “A lot of fun. It was great.”
So who exactly is Castro?
The 18-year-old is a native of San Antonio de Guerra, a municipality in the Santo Domingo province of the Dominican Republic. Castro aspired to be like Winter League role model Emilio Bonifacio -- a former Marlin -- and Mets slugger Juan Soto. An older cousin of his even competed in the Dodgers’ system.
“Since I was 3 years old, I just remember playing with a plastic bat in my backyard, and just taking a lot of swings inside the house,” Castro said. “I think I broke a couple TVs, to be honest.”
The 6-foot-3, 180-pound Castro, who was part of the Marlins’ 2024 international signing class, has made a big jump in his second professional season. In 52 games in the DSL in 2024, Castro had a .148/.333/.254 slash linewith three doubles, five homers, 22 RBIs, 44 walks and 73 strikeouts. In as many games this season, he has a slash line of .264/.399/.585 with 14 doubles to go along with his 16 homers (most in the DSL since at least 2006), 51 RBIs, 34 walks and 62 strikeouts.
Of everything Castro has accomplished so far this season, however, he is most proud of the trust he has gained in himself, his friendships around the clubhouse and knowing how to behave as a pro ballplayer.
So what exactly led to this big jump?
In one of Marlins director of international scouting David Hernandez-Beayne’s initial scouting reports, Castro was described as a long-limbed corner outfielder with raw explosive power and room to fill. He has the “rare combination of size, strength, looseness and pliability.” His plus power was paired with “enough contact skills and plate discipline to provide a high offensive floor.”
All of the ingredients for success have been there; it was a matter of experiencing growing pains and learning from them. Castro credits daily work with the coaches and time in the gym for his success this year.
“My physique has helped me, has grown, but also a lot of data that we've been doing and analytics like hitting contact and specifics that I have learned,” said Castro, who can squat upwards of 405 pounds. “Most important to improve was making good decisions, just swinging at balls that you can damage.”
The teenager can still add to an already impressive campaign in his first taste of the DSL playoffs, which begin on Thursday. And if Castro continues to show progress, he will be expected to be an impact player stateside in 2026.
“There’s nothing anyone can say about him that is negative,” Hernandez-Beayne wrote to MLB.com. “He’s diligent, hard-working, never complains. Is the ultimate worker and always goes about his business. He is very passionate and is also very open-minded and always open to new concepts.”