SAN FRANCISCO -- From the loss of starter Blake Snell to injury to a stunning opposing rally in the ninth inning, the Giants took one blow after another as they fell, 7-5, in Sunday's series finale and were swept in three games by the Yankees at Oracle Park.

The team announced Snell's injury as a tight left groin, similar to the left adductor strain that had caused him to miss a little more than a month earlier this season. As with that injury, which he sustained during a bullpen session, Snell said he only felt something on the final pitch he threw.

Snell had thrown a season-high 99 pitches (56 strikes) and was two pitches into an at-bat against Alex Verdugo in the fifth inning when manager Bob Melvin and a trainer came out to remove the Giants' left-hander from the game. Snell is scheduled to undergo an MRI on Monday.

"I don't think he's moving around worse than last time, but I don't know how it's not an IL [stint]," Melvin said.

It was Snell's third start since returning from the 15-day injured list on May 22 in Pittsburgh. Before this season, Snell had also been sidelined with left adductor issues in 2021 and '22.

Snell said it's possible that a mechanical change could help him get over the recurring injuries. He noted that he uses his back leg a lot in his delivery, which could potentially lead to him tweaking that troublesome left groin area.

"We'll look at it," Snell said. "I've definitely got to add something strengthening-wise that I haven't been doing. … I've got a lot to learn, but I've definitely got to get stronger and make sure that this stops happening."

Before his early departure, Snell, who joined the Giants on a two-year, $62 million deal (with an opt-out after 2024) at the end of Spring Training, had been putting together one of his best starts with San Francisco.

"He's a slow starter in the season anyway, so this is about the time where you start to pick it up," catcher Curt Casali said. "He was on his way to a really good outing. Unfortunately, sometimes these injuries can just trickle back and bite you a little bit."

Snell allowed a solo home run in the first inning to Juan Soto -- who later flipped the script on the Giants and closer Camilo Doval with a go-ahead two-run shot in the top of the ninth -- but tossed three scoreless frames leading up to the fifth.

Snell loaded the bases on back-to-back singles and a walk before his departure. Rookie left-hander Erik Miller entered the game and inherited a 1-1 count against Verdugo with the bases loaded and two outs, then surrendered a game-tying two-run double.

In all, Snell allowed three runs, all earned, on five hits and three walks while striking out a season-high-tying seven batters. He felt that he was in a good place before sustaining the injury, with better feel for his pitches compared with his first five starts of the season.

"It's all coming together," Snell said. "I was really confident about it, even the Soto homer, just missed middle. … It's definitely a bummer, and frustrating. But I've got to look on to what's next and attack that and get better, and get back on the field."

Now, the Giants have two rotation spots to fill before the return of rookie Keaton Winn (right forearm strain). Winn is close, with a rehab start for Triple-A Sacramento set for Tuesday.

Right-hander Spencer Howard, who tossed four scoreless innings in relief in his Giants debut last Tuesday, is expected to pitch on Monday in Arizona and could be a candidate to start.

The other healthy starters on the 40-man roster have both struggled in their limited big league experience. Mason Black posted an 8.79 ERA in four appearances (three starts), and Kai-Wei Teng recorded a 9.82 ERA in four relief appearances. Landen Roupp, the club’s No. 11 prospect per MLB Pipeline, has pitched well for Sacramento but is on the 7-day injured list.

The Giants knew their six-game homestand against the Phillies and Yankees, the top two teams in baseball, would be a challenge. But additional injuries to key players bookending the two series -- LaMonte Wade Jr. (right hamstring strain) on Monday and Snell on Sunday -- made a tough week even harder.

"It's still tough to [evaluate the team] because we're not looking at a full roster at this point," Melvin said. "I think the one thing that we can take away is that some of the younger guys have come up and done well, especially in big spots."