Marlins minor league report: Starting pitching standouts and stolen base mania continues

Welcome to another edition of what will be a series of weekly Miami Marlins minor league summaries throughout the 2025 season.

The stats and information used below is updated entering April 15 unless otherwise noted.

Triple-A Jacksonville

Right-hander Adam Mazur made one start and a long relief appearance this past week for the Jumbo Shrimp. On Tuesday, Mazur tossed five shutout innings, allowing one hit and walk while striking out five.

In that Tuesday start, Mazur leaned on his slider and four-seamer. The fastball averaged 93.7 mph and topped out at 95.9 mph. His slider generated eight whiffs and was used in three of his five strikeout pitches (curveball for two strikeouts).

On Sunday, Mazur entered in relief of Declan Cronin, who was making a rehab appearance. In 4 ⅓ innings of work, the Fish On First 11th-ranked prospect struck out five and, for a second time in the week, did not allow a run.

Mazur is already on the 40-man roster, so if he continues performing like this, the big league team will give him an opportunity to start for them at some point this season.

In a Wednesday afternoon game, starter Janson Junk turned in the best start of his career at any level, going six shutout innings, striking out ten and not walking anyone. The Jumbo Shrimp were facing a Charlotte Knights lineup featuring top prospects Kyle Teel, Edgar Quero and Colson Montgomery.

Junk generated 11 total whiffs, with six of them coming on the fastball, which averaged 94.4 mph and topped out at 96.3 mph. After a strong spring for the Marlins, Junk was reassigned to Minor League camp and then AAA-Jacksonville. He’s currently proving to be a strong depth option for the Marlins.

In his first start for the Jumbo Shrimp, Valente Bellozo went four shutout innings, striking out six and only walking two. Bellozo’s fastball topped out at 92.5 mph and averaged 90.7 mph. His cutter generated eight whiffs (13 total whiffs on the night).

Reliever Austin Roberts, who the Marlins picked up in the minor league phase of the Rule 5 Draft a couple years back, is posting a 0.90 ERA, 3.90 FIP, 9.00 K/9 and 7.20 BB/9 through five games this season.

On Sunday, Roberts started for the Jumbo Shrimp and went two shutout innings, walking and striking out three. The fastball velo jumps out, averaging 94.9 mph and topping out at 96.5 mph. His arsenal consists of the fastball, cutter, curveball and changeup.

Although Jakob Marsee won’t blow you away with his batting average, he is someone who you can rely to get on base plenty. Through 14 games, Marsee is slashing .214/.421/.357/.778 with one home run, four RBI and 13 stolen bases, which leads all of Minor League Baseball.

Entering April 16, the Jumbo Shrimp lead MiLB with 45 stolen bases. The team right behind them? The Beloit Sky Carp, the Marlins' High-A affiliate. It has been made very clear that the organization will be aggressive on the base paths.

Despite not being called up to replace the injured Nick Fortes, Agustin Ramirez continues to put up big numbers in Jacksonville. As he’s played almost every day, he’s slashing .280/.345/.520/.865 with two home runs and 11 RBI. His biggest flaw continues to be on the defensive side of the ball as he has six passed balls, more than any other catcher in the minors. Receiving is also a part of his game where he continues to struggle in, but the bat is more than ready. On April 11, the club's control of Ramirez was extended through the 2031 season.

Double-A Pensacola

Kemp Alderman continued his hot start to the season and is now slashing .375/.432/.750/1.182 with three home runs, 11 RBI and five stolen bases. He has already matched his 2024 total in the stolen base category. Alderman was selected to the MLB Pipeline Prospect Team of the Week.

There's been a significant change to his batting stance that could be contributing to the success he's having at the plate.

It was a weird outing for lefty Robby Snelling (FOF #6). He gave the Wahoos 5 ⅓ innings of work, allowing four runs (three earned) off of eight hits, one walk, and nine strikeouts. He also surrendered two home runs. Through two starts, Snelling has posted a great 2.61 ERA, but his expected FIP is even better at 2.04.

On Tuesday, catcher Joe Mack (FOF #8) hit his first home run of the season and is now slashing .348/.483/.696/1.179 with two home runs and four RBI. His second home run came on Friday.

In his second start of the season, Dax Fulton went 5 ⅓ innings of work, allowing two runs off of five hits, walking two and striking out four. This is off the heels of a start where he was only able to go three innings of work.

Quietly, Adam Laskey went four shutout innings, allowed one hit, didn’t walk anyone and struck out nine.

In three appearances, reliever Josh Ekness has yet to surrender a run. He’s struck out six and yet to walk a batter. Like Ekness, Zach McCambley has made three appearances this season and has struck out nine and only walked two. If healthy, McCambley can find himself on a fast track to Miami.

High-A Beloit

The Sky Carp came out swinging against the Cedar Rapids Kernels, winning 10-0 and 8-7 in their second and third games of a six game series, but dropped the final three. Even more so than their Low-A counterparts, stolen bases continued to happen in abundance for Beloit. They stole an audacious 26 bases in six games. They have 44 steals on the season entering play on April 16; the next closest Midwest League team has 21.

One huge catalyst for the stolen base success of Beloit in this series was Emaarion Boyd who came over in the Jesús Luzardo trade this offseason. In the second game of the series, a Sky Carp 10-0 win, Boyd stole an insane six bases. It all happened without the benefit of a hit. Boyd went 0-for-1 and walked twice. He was also hit by a pitch. During all three times on base, Boyd stole both second and third base.

Boyd has appeared in nine games for Beloit this season as the primary center fielder. He’s gotten off to a slow start swinging the bat, but has proven he will make the most of his trips around the bases. With advertised 70-grade speed, if Boyd can find more consistent contact rates while continuing to work counts, he will become an annual 25+ stolen base threat with the ability to cover all necessary ground in center field. He also owns an above average throwing arm. We will continue to watch his contact rates closely as the season progresses.

After being limited by injury in most of his MiLB career and struggles with offensive consistency last season, Yiddi Cappe is back in Beloit for a third year. Splitting time between second base and DH, his first six games have been extremely encouraging. In this series, Cappe went 7-for-15 with three walks. He had just one extra-base hit, a double, but he made the most of his trips around the bases, stealing three and scoring six runs.

On top of his ability to stay on the field, there have been consistent questions about his physical projection. Yiddi is still and will always be a wiry athlete, but he’s begun to quiet down his approach and not over-swing. With smoother mechanics, Cappe’s on-base numbers have thrived early this season. Defensively, it seems Yiddi’s chances at sticking at shortstop are now gone especially with the improvements to the Marlins’ system. If his power remains limited, third base may not be the best choice either. However, Cappe still has the ability to play a solid second base. His time at DH also appears to be allowing him to focus fully on offensive consistency. Expect this early season trend of 2B/DH to continue. And remember: Cappe is still just 22. Don’t write him off; the Marlins sure haven’t.

Noble Meyer (FOF #5) made a somewhat delayed first start in this series. During spring training, he missed some time with fluid build-up in his throwing arm, which is highly likely the reason he did not debut in the first series. Meyer got off to a very solid start to his sophomore season, pitching into the fifth inning without allowing a run. He allowed three hits while walking two and striking out two.

As he told us during spring training, the focus for Meyer this year will be staying as close to 100% as possible. Last season, he was hampered by a nagging back injury which inhibited him most of the season, especially in relation to his repeat his delivery. On top of that, Meyer is also hoping to showcase improvements to his slider which is now a sweeper and a more consistent changeup. During the second half of 2024 and also in this start, his fastball velocity was down a bit from where he was early last year, but as strength and repeatability fully return and as Noble gets fully acclimated to his new arsenal, it has the capacity to return back up to approx. 94 mph. 2024 wasn’t what Noble wanted, but he has the stuff, ability, and drive to come back better than ever this season. His initial output looked good.

Low-A Jupiter

Jupiter started the series against Dunedin sloppily, walking a franchise record 22 batters and allowing 19 runs, but bounced back well to split the series. They stole 15 more bases and now have 33 stolen bases in nine games.

After striking out eight in 3 ⅔ innings in his season debut, what could Liomar Martinez do for an encore? How about strike out another nine in four innings. Martinez was once again almost unhittable, particularly with a staple 12-6 curveball. He was even more dominant than his first outing as he didn’t allow a walk. The only blemish on his record was a single hit.

A converted infielder who has an interesting backstory, Martinez is throwing strikes at an eye-popping rate. In this outing, he had a 50% CSW%. Still just 19 with budding stuff and improving control, Martinez has a starter’s ceiling. With continued success, it would behoove the Marlins to put him in a rotation and allow him to build a five-day routine.

Dillon Head (FOF #9) built off a solid opening series by getting on base in four of five games played against Dunedin. His standout game occurred on Tuesday when he went 2-for-5 with his first home run of 2025. He also recorded his first walk of the season.

To start his 2025 campaign, Head is swinging at a lot of pitches, but is doing enough to at least spoil pitches and lengthen at-bats. His swing decisions will need to improve as he makes his way up the MiLB ladder, but against Single-A pitching, he’s been able to hold his K rate in check. Coming back from a missed second half, this is a great start for Head. With reps being the most important thing right now, we will continue to see him play daily with Jupiter.

The young phenom Andrew Salas (FOF #4) isn’t playing every game with the Hammerheads, but he’s making the most of his reps. Described by the coaching staff as a “super-utility," Salas got into three of six games in this series against Dunedin. At the plate, his advertised approach well beyond his years showed true. He went 3-for-10 and walked three times while striking out three times. He also scored three runs.

Salas is with the Hammerheads as the youngest player in the FSL. If the 17-year-old continues to perform, he may stick with the Hammerheads all year, but it may be advisable for the Marlins to get him regular reps at a position of their choosing when FCL season begins. Salas has been described as a guy the team wants to see more of at shortstop, but that he’s also capable of playing center field. So far with Jupiter, with traffic around, he’s only spent time in center field sans one game at second base. He has not taken the field at shortstop. FCL season starts on May 5.

Next Up (April 15-20)

• Triple-A Jacksonville at Memphis
• Double-A Pensacola at Columbus 
• High-A Beloit vs. Quad Cities
• Low-A Jupiter at Daytona

Interested in learning more about the Miami Marlins' top prospects? Check out our comprehensive top prospects list that includes up-to-date stats, articles and videos about every prospect, scouting reports, and more!