Marlins add trio of Top 30 prospects to 40-man roster

MIAMI -- The Marlins selected the contracts of all three of their Top 30 MLB Pipeline prospects eligible for the Rule 5 Draft ahead of Tuesday's deadline: Minor League home run champion Deyvison De Los Santos, middle infielder Jared Serna and left-hander Dax Fulton.

The 21-year-old De Los Santos, who ranks as Miami's No. 4 prospect, came over to the Marlins' organization on July 25 as part of the A.J. Puk trade with the D-backs.

Around this time last year, Arizona left De Los Santos unprotected and Cleveland selected him in the Rule 5 Draft before returning him in March. He would go on to lead all Minor Leaguers in homers (40) and RBIs (120). Since 2022, De Los Santos has driven in the most runs (287) in the Minors.

"Deyvison De Los Santos is one that, on video and talking with our group, [we're] just super excited about," director of Minor League operations Hector Crespo said in September. "I don't know the last time we had a power threat component that he possesses, to just have someone walk up to the plate and immediately feel like he's going to do damage."

De Los Santos’ breakout 2024 season began at Double-A Amarillo, where he hit .372/.426/.696 with four doubles, one triple, 14 homers and 37 RBIs in 38 games. De Los Santos didn't miss a beat with a promotion to Triple-A Reno, as he slashed .289/.338/.588 with 14 doubles, one triple, 14 homers and 47 RBIs in 49 games. Following the trade, his numbers dipped to .240/.284/.459 with seven doubles, 12 homers and 36 RBIs in 50 games.

According to MLB Pipeline's scouting report, De Los Santos' raw power and exit velocities rank among the best in the Minors due to his bat speed and strength. But he must make better swing decisions, as evidenced by his 144 strikeouts and 34 walks in 2024.

Miami sent De Los Santos to the Dominican Republic Winter League, where he entered Tuesday with a slash line of .260/.296/.320 with one double, one triple, five RBIs, 10 strikeouts and three walks in 17 games for Gigantes del Cibao.

After beginning his professional career as a third baseman, De Los Santos saw the majority of his time at first base in 2024. That position is currently blocked at the Major League level by Jake Burger and Jonah Bride.

Like De Los Santos, Serna joined the organization in a midseason trade -- with the Yankees for Jazz Chisholm Jr. -- and quickly made a name for himself.

Miami's No. 10 prospect collected 15 extra-base hits in 39 games at Double-A Pensacola before earning a promotion with six games left of Triple-A Jacksonville’s season and going 2-for-20. Not only does the undersized Serna have a naturally compact right-handed stroke but he also makes good swing decisions (101 strikeouts to 56 walks). The Marlins are hopeful the 22-year-old can stick at shortstop, where he saw more action during the 2024 season.

"Serna has obviously kind of lit the world on fire, which is really cool to see," said director of player development Rachel Balkovec, who knew Serna from their time in the Yankees’ organization.

The 23-year-old Fulton, the top prep southpaw in the 2020 MLB Draft whom the Marlins selected 40th overall, is recovering from a second Tommy John surgery. In 2023, he had been on track to possibly make his MLB debut after being a non-roster invitee at big league camp and pitching in seven games (six starts) for Double-A Pensacola.

Before the June 2023 procedure, Miami's No. 26 prospect stood out with a plus curveball and slider. His four-seamer could reach 97 mph and his two-seamer had less velocity and more sink. The 6-foot-7, 235-pounder also had been developing a changeup.

"Dax is pretty close," Balkovec said in September. "[He's] doing fantastic in the rehab system."

With these additions, the 40-man roster is full.