San Diego Padres All-Star reliever Jason Adam toppled to the surface of the mound Monday night and had to be carted off the field after trying to field a ground ball in the top of the seventh inning against the Baltimore Orioles.

After the game, a 4-3 Padres’ loss, manager Mike Shildt said Adam suffered a ruptured quadriceps tendon.

“Our prognosis early is not favorable,” Shildt said. “I mean, things can change, but it’s a quad tendon rupture. It’s pretty clear and pretty serious.

“Don’t want to be too bleak but it’s not overly positive.”

Adam will undergo an MRI to confirm the rupture, which would end his outstanding 2025 season. The recovery time is between six and nine months, so he should return early in the 2026 campaign.

In his second inning of work, Adam had a runner on first and one out and was facing Gunnar Henderson. Henderson hit a grounder up the middle and Adam attempted to move from left-to-right for the ball, but crumpled to the ground as the ball got past him for an infield single.

He was replaced by Robert Suarez, who gave up a two-out single to Dylan Beavers that scored the go-ahead run and tagged Adam (8-4) with the loss.

Adam, 34, has been a stalwart in San Diego in his two seasons. He came over from Tampa Bay at the 2024 trade deadline and, entering this evening’s game, had a 1.58 ERA for the Padres in 91 career games.

He was making his 65th appearance of the season on Monday and likely finishes the season with a 1.93 ERA, fanning 70 batters in 65 1/3 innings.

Adam has pitched for Kansas City (2018), Toronto (2019), the Chicago Cubs (2020-21) and Tampa Bay (2022-24).