MIAMI -- If the Marlins want to reach the playoffs for the first time in a full season in 20 years, they will have to do so without their ace. Right-hander Sandy Alcantara announced that he is done for the 2023 season prior to Miami’s 5-4 win over Milwaukee on Saturday afternoon.

"Very frustrating for me," Alcantara said. "A guy like me who always likes to compete -- I feel sorry for all the fans, my family, my son, my friends, for the city -- because I'm not going to be out there this year. Hopefully I've got to be ready for next year. I don't know, so I've just got to be positive."

Alcantara was unsure of the next step, saying he would have to get together with his agent Adriel Reyes, Marlins general manager Kim Ng and manager Skip Schumaker to make a decision -- one that could include surgery and potentially impact his 2024.

"I don't know," Alcantara said. "I can't say yes, I can't say no, so I've just got to keep positive and just talk then and see what they say."

Initially diagnosed with a right forearm flexor strain, Alcantara was placed on the 15-day injured list for the first time in his career with an arm issue on Sept. 6 after feeling discomfort on his 94th and final pitch on Sept. 3 in Washington. An MRI then revealed a right UCL sprain.

Ten days after that diagnosis, the 28-year-old played catch on flat ground in Milwaukee. Just five days ago, Alcantara was hopeful he could return this season after throwing two pain-free bullpen sessions. He began a rehab assignment with Triple-A Jacksonville on Thursday, throwing four scoreless innings on 51 pitches (34 strikes) and maxing out at 98.3 mph. But he shut himself down after experiencing forearm tightness and traveled back to Miami.

"I was so happy before I got there to the Minor Leagues," said Alcantara, whose forearm feels better than it did during the game. "I felt great in my bullpen [sessions], but I just felt something over there in the Minor Leagues, [in the] third inning. I talked to my trainer and made the decision to not go out there anymore."

Until his injury, Alcantara led all qualified pitchers with 858 1/3 innings pitched since 2019, including back-to-back 200-plus-frame seasons from '21-22. His 6.66 innings per start over the past three years were the highest by any qualified starter in a three-year span since Corey Kluber averaged 6.74 IP per start from 2016-18.

Though Alcantara wasn't as sharp this season, with a 4.14 ERA and a 1.21 WHIP over 28 starts compared to his 2.28 ERA and 0.98 WHIP in his 2022 NL Cy Young season, he remained a workhorse; as of Saturday he was tied for an MLB-leading three complete games (one shutout).

"Sandy is an absolute warrior," Schumaker said. "Great teammate -- wanted to do everything he could to come back, and he tried. ... I think that goes a long way in that clubhouse when, maybe throughout the years, some guys have pulled the chute on some minor things. The guy was hurt and still tried to make it, still tried to help us, and it shows what he's all about and what he means to us. He's going to be around -- we need him around. It's bad news, obviously -- that's not good news -- but it just shows you who he is."

The Marlins (79-75) entered Saturday one game back of the Cubs (80-74) for the third NL Wild Card spot. Alcantara was on the mound when the franchise snapped a 17-year playoff drought in 2020, recording a quality start in an NL Wild Card Series Game 1 victory over the Chicago at Wrigley Field.

"I think the thing that broke my heart [is] not being able to go [out] there with my teammates, competing," Alcantara said. "It doesn't matter what happens. I've just got to keep supporting them in here, out there, inside, everywhere they are. So hopefully we make the playoffs this year without me, so I'm just going to be here supporting."