WASHINGTON -- In many ways, Marlins right-hander Adam Mazur is a different pitcher than the one who appeared at Spring Training with an outside shot at the fifth rotation spot.
The grips on his two-seamer, changeup and sweeper have been tweaked. His mechanics focus on hunching over a bit more to get more into his abs to sync his lower half up.
Mazur, ranked as Miami’s No. 15 prospect, took the mound on Tuesday for his third start with the ballclub and 11th overall in the big leagues.
It was a mixed bag, as Mazur matched a career high with six innings but gave up all five of Washington’s runs in Miami’s 5-2 loss at Nationals Park. He didn’t walk a batter for just the second time in his career, struck out five (second most) and tallied his highest slider usage (47.8%, minimum 50 total balls).
“It's all been kind of a work in progress," Mazur said, "and now it's just a matter of getting it all to click and show up at the right time."
Some of the damage on Mazur’s line was a case of bad luck.
Washington tagged him for a pair of runs in the second with some weak contact. Daylen Lile (81.5 mph exit velocity) and Riley Adams (80.9 mph) blooped back-to-back doubles off of Mazur, who later coughed up an RBI single (102.8 mph) to Jacob Young. In the third, Mazur allowed another run on a softly hit ball. Following CJ Abrams’ leadoff double, Mazur recorded the next two outs before Lile golfed an RBI single (68.3 mph) to left.
Mazur’s biggest mistake came on the center-cut 95.2 mph four-seamer James Wood drilled to left for a two-out two-run homer in the fourth.
“I got two good pitches to hit the first two pitches I saw today,” said Wood, who singled in the first and grounded into a double play in the second. “I had to work a little bit more to get a better pitch later in the game.”
The 24-year-old Mazur bounced back to toss scoreless fifth and sixth innings to end his start on a positive note. In the latter frame, he fanned Wood swinging on a sweeper -- the first of his career -- for the second out of the inning with a pair of runners in scoring position.
“Just the way I went out there and battled,” Mazur said. “Some of those innings could have snowballed quickly, but try to keep them to one to two runs. Just a little unfortunate there in the second and third, and then [in the] fourth I've got to make a better pitch.
“Just come up here and do what I was doing. I started to figure some stuff out back in Jacksonville, and just wanted to take that up here.”
With six starting pitchers on the injured list, Miami’s rotation is in flux behind righties Sandy Alcantara and Eury Pérez.
Right-hander Edward Cabrera is undergoing further evaluation on his right elbow, while righty Janson Junk (right ulnar nerve irritation) went five innings to begin a rehab assignment with Triple-A Jacksonville on Tuesday. Manager Clayton McCullough said pregame that Junk would rejoin the pitching staff in Miami if he came out of that outing feeling good. Lefty Ryan Weathers (left lat strain) will get at least one more rehab start before the club considers reinstating him.
So Mazur, who had spent nearly all of 2025 at Triple-A Jacksonville, where he compiled a 4.36 ERA in 22 games (19 starts), was recalled last Thursday against the Mets in Queens (4 IP, 2 ER). He had made a spot start in Miami on June 18, when he gave up four runs over 5 2/3 innings to the Phillies in his club debut, before returning to the Minors.
Over the season’s final month, Mazur will get a chance to show his development. Aside from the results, the organization will take into account the underlying metrics.
“One, it's the stuff,” McCullough said. “How well does the stuff hold throughout the outing? The ability to throw multiple pitches in the strike zone if you're behind in the count, and then as well as, overall, just the ability to fill up the zone. Adam did that night, limited the free passes, was able to get some punch, got some swing and miss.
“So those are really good signs. Can you get some miss? And it always is going to start with the ability to access the strike zone, and if you're able to do that with multiple offerings, just gives you a chance to keep hitters off-balance.”