Miami Marlins left-hander A.J. Puk, converted from a reliever to a starter this season, was placed on the 15-day injured list on Saturday because of left shoulder fatigue.

Puk, who turns 29 on Thursday, fell to 0-4 with a 9.22 ERA on Friday in Miami's 8-3 loss to the host Chicago Cubs. After sitting out nine days between outings because of the flu, Puk threw just 40 of 70 pitches for strikes in allowing seven runs, seven hits and three walks with four strikeouts in three innings.

"Just kind of one of those days," Puk said. "Just trying to get those outs and couldn't."

Puk has allowed 19 hits and a major league-worst 17 walks. He is tied for the MLB-lead in losses -- four in his four games, all starts. For his four previous seasons with Oakland (2019, 2021-22) and Miami (2023), he was a pure reliever in 142 appearances. He is 13-15 with a 4.18 ERA for his career.

"I think A.J. has been dealing with a little bit ever since the cramping in the hand and the grip issues he had a few games ago," Marlins manager Skip Schumaker said. "It just really didn't get back on track. ... He feels like this isn't going to be too long of a stint. The conversation moving forward and what exactly that means for him, we'll have internal discussions about that."

Miami starters Sandy Alcantara and Eury Perez already are out for the season with Tommy John surgery, and left-hander Braxton Garrett (shoulder) is on the IL.

In other moves Saturday, the Marlins recalled Roddery Munoz from Triple-A Jacksonville and selected the contract of fellow right-hander Kyle Tyler from the Jumbo Shrimp. Left-hander Josh Simpson was transferred to the 60-day IL with left elbow ulnar neuritis.

Munoz, who turned 24 on Sunday, was scheduled to make his major league debut in the second game of the Marlins' doubleheader against the Cubs on Saturday night.