MIAMI -- You'd be hard pressed to find stronger Nos. 1-3 in the rotation than Sandy Alcantara, Pablo López and Trevor Rogers. The trouble for the Marlins is finding two arms to round out the starting staff.

Rookie southpaw Daniel Castano, recalled from Triple-A Jacksonville to start on Saturday, allowed three runs across four innings in a 6-2 loss to the Brewers at loanDepot park. The defeat snapped a four-game win streak during which the pitching permitted just five runs. Milwaukee matched that through five innings.

With Elieser Hernandez not expected to return until late May and top prospect Sixto Sánchez out until sometime in June, the Marlins will have to make due in the rotation until then. Unfortunately for Miami, no one has taken command of a spot.

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“Really, just disappointed that I let the team down,” said Castano, whose ERA jumped to 5.19 and his WHIP to 1.56. “We're kind of on a good winning streak. I know what I can do here, and I'm pretty confident in going against these guys, and I just need to execute better. Sometimes that's just the way the ball goes, but I wanted to do my part for the team for sure.”

Castano equaled his season total in strikeouts (five) but walked in a run and surrendered a long ball to right-hander Adrian Houser for the second straight outing. It marks the first time a pitcher has hit a homer off the same pitcher in two separate games within the same season since 2006, when Bronson Arroyo did so off Glendon Rusch. Castano has been unable to give the Marlins length in four starts, with a season high of five innings -- achieved in each of his first two outings. The Marlins split those games. They have lost his last two.

Manager Don Mattingly said the lack of routine for Castano, who last pitched in a game on April 27 in Milwaukee, makes it tougher to keep a schedule. He was optioned to the alternate training site two days later. Despite that, Castano noted he felt good, with a live session under the guidance of pitching coach Mel Stottlemyre Jr. earlier in the week.

The 26-year-old lefty can draw upon his success from last season, when he posted a 151 ERA+ in seven games (six starts). Like 2021, Castano was called into action out of necessity.

“Unfortunately, that's just not the situation that he's in right now,” Mattingly said. “It's something that he's just going to have to deal with, and obviously moving forward, he has a chance to do that. When you're going back and forth and trying to make moves and manipulate the rotation a little bit because of off-days and things like that, there's somebody that's having to pitch on nine days’ rest and 10 days’ rest. It's not ideal, but it is the role that they're in right now. And so they have to do the best they can.”

Before being optioned to Jacksonville, No. 10 prospect Nick Neidert made three underwhelming starts for the Marlins; he was unable to complete five innings in each. He allowed three unearned runs over five innings on Friday night for the Triple-A affiliate.

On Wednesday, the Marlins executed a bullpen game to perfection in an 8-0 win over the D-backs. That spot in the rotation will return on Monday to begin a 10-game trip. No. 22 prospect Jordan Holloway, one of five relievers to pitch, has been a starter in the Minors and built up his pitch count to 61. He is a possibility to open that game in Arizona.

"In terms of these guys stepping in, I think they've definitely done a serviceable job," general manager Kim Ng said during Friday night's Bally Sports Florida broadcast. "I think one of the things that's clear to me is that we do have depth, we have depth on the 40-man roster, which is so important over the course of 162 games. … I think with every stint that Castano, Neidert, Holloway have, they learn so much more. Look at Rogers: He was up for less than two months last year, now look at him. I think this is just experience, it's knowledge, and also getting used to crowds."