SAN FRANCISCO -- With their playoff hopes expiring, the Giants seem likely to shift into development mode in September and begin auditioning young players who could have a chance to break into bigger roles in 2025.

Chief among them will be Mason Black, who was recalled from Triple-A Sacramento on Saturday to fill in for the injured Robbie Ray.

Black struggled to stick in his first look in the Giants’ rotation, but the 24-year-old right-hander took a step forward after returning to the Majors for the first time since May 23, allowing two runs over a career-high five innings in a 4-3 loss to the Marlins at Oracle Park.

“I didn’t get through that fifth the last couple of times I was up here, so it meant a lot just to get my feet wet again and be able to go back out there and hopefully get more innings in the future,” Black said.

Black, the club’s No. 8 prospect per MLB Pipeline, logged an 8.79 ERA over his first four big league outings this year, but he worked on some mechanical adjustments at Triple-A, focusing on staying more upright to help make his delivery more repeatable. He earned his second callup after recording a 2.91 ERA over four starts for the River Cats in August and continued to build on that success against the Marlins.

Leaning primarily on his four-seam fastball, sweeper and sinker, Black struck out three of the first four batters he faced, though he was hurt by a misplay from shortstop Tyler Fitzgerald, who flubbed Jonah Bride’s routine grounder up the middle with one out in the second. Official scorer Jim Young credited Bride with a single, which helped set up Griffin Conine’s two-out, two-run blast off the right-field foul pole.

“If I come up with one of those plays early in the game, that homer probably doesn’t happen,” Fitzgerald said. “[Black] did really great. It was good to see.”

Black rebounded by retiring nine of the final 11 batters he faced en route to completing five innings for the first time in five Major League appearances. He gave up four hits while walking none and striking out a career-high six and departed with the Giants trailing, 2-1.

“I thought he looked good,” manager Bob Melvin said. “He just gave up the one homer. Five innings, a couple of runs. He did his job.”

Left-hander Taylor Rogers came on to replace Black in the sixth, but he surrendered a leadoff homer to Connor Norby that extended the Marlins’ lead to 3-1. The Giants pulled within one on Fitzgerald’s RBI single in the bottom half of the inning, but Miami added a key insurance run with the help of a controversial call in the seventh.

Otto Lopez opened the inning with a leadoff walk against Spencer Bivens and then took off for second base, but he appeared to be thrown out after catcher Patrick Bailey’s throw beat him to the bag. Still, Fitzgerald was called for obstruction after planting his left foot in front of the base to receive the throw and apply the tag, and Lopez was awarded the base.

Rule 6.00(h) awards the base to the runner when the fielder is ruled to have impeded the runner’s progress while not in possession of the ball and not in the act of fielding the ball. The rule is non-reviewable and leaves the interpretation up to the judgment of the umpires, who conferred briefly before upholding the initial ruling.

“They called it obstruction there, and I don’t know how that affects the play,” Melvin said. “His foot is in front of part of the bag, but when you’re sliding to the back of the bag, you’re trying to make a tag and it doesn’t affect the play. I don’t know how you can make that call. There should be some feel involved with that.”

Lopez went on to score on a pair of groundouts, which proved to be the difference in the game after Michael Conforto blasted a solo shot to once again cut the deficit to one in the eighth. The Giants finished only 1-for-7 with runners in scoring position and went down quietly against Calvin Faucher in the ninth, slipping back under .500 (68-69) with 25 games left to play.

“I thought it was a terrible call,” Fitzgerald said. “My foot was originally in front of the bag, but I pulled it back. Maybe by rule it was obstruction, but in no way did I obstruct the runner. If you look back and watch the replay, he slid in and he was able to get to the bag. I tried to move my foot so he was able to reach the bag, and I didn’t think I was obstructing at all.”