The Marlins are set to recall left-hander Dax Fulton from Triple-A Jacksonville, Isaac Azout of Fish on First reports. Righty William Kempner, who made his own big league debut last night, will be optioned to Jacksonville in his place. Fulton has been a starter for the vast majority of his professional career but will make his debut in the Miami bullpen, Azout adds. Barry Jackson of the Miami Herald reports that left-hander Robby Snelling is still on track to make his big league debut Friday in place of recently DFA’ed veteran Chris Paddack.
Kempner tossed only eight pitches in last night’s debut, so it’s not a matter of him being unavailable. Perhaps the Marlins simply wanted another lefty in the ‘pen after Andrew Nardi tossed 22 pitches yesterday, or perhaps they preferred to add some more length after using five relievers Tuesday. Whatever the rationale, Fulton will head to Miami for his first call to the majors. He’s made five starts and two relief appearances this season in Jacksonville but been hit hard: 20 innings, 17 earned runs, 23 hits, 11 walks, three hit batters and 24 strikeouts.
It’s been a shaky start to his year, clearly, but Fulton is a former second-round pick and well-regarded prospect whose path to the majors has been set back by injuries. Most notably, he underwent an internal brace procedure on his left UCL in June 2023. (Fulton also had Tommy John surgery as an amateur.) That 2023 surgery wiped out his entire ’24 campaign. Fulton returned in 2025 with 103 2/3 innings, posting an unsightly 5.38 ERA with more encouraging underlying marks (3.55 FIP, 23.8% strikeout rate, 47.3% grounder rate).
Fulton is a towering 6’7″ southpaw who’s listed at 245 pounds. He’s sitting 93.6 mph on his heater and can ramp the pitch up to 96-97 at times. The big lefty’s other go-to offerings are a low-80s curveball and an upper-80s changeup, though he’ll occasionally sprinkle in a sinker.
Whether the move to a relief role has any permanence remains to be seen. The Marlins have a good bit of rotation depth even after Paddack’s DFA and offseason trades of Edward Cabrera and Ryan Weathers. The current staff includes Sandy Alcantara, Eury Pérez, Max Meyer and Janson Junk. Snelling, who sits 26th on Baseball America’s just-released update of their top-100 prospects, seems ticketed for a debut Friday.
Fellow lefty Thomas White, ranked even higher at No. 11 overall, will likely debut at some point this season. The Fish also have talented lefty Braxton Garrett in Triple-A — he started last night and is thus not a candidate to return to the big league rotation Friday — alongside swingmen Ryan Gusto and Bradley Blalock. Jacob Miller and Karson Milbrandt, the team’s second- and third-round picks in 2022, are both in their second stints at the Double-A level (with the latter throwing very well at present).
That stock of arms could make the bullpen Fulton’s clearest path to carving out a lasting spot on the big league roster, but he’ll likely need to get back to his pre-surgery form with another stint in Triple-A regardless. If he’s up to provide some length in the bullpen for the next couple days, he’ll be a candidate to be sent back down to Triple-A on Friday — assuming Snelling is indeed promoted for his debut that day.
