ANAHEIM -- Left-hander Patrick Sandoval was hopeful he avoided major injury after exiting Friday’s game against the Dodgers with a left elbow strain, but revealed the rough news before Monday's 5-1 series-opening win over the A's that he suffered both a high-grade flexor tendon tear and a torn ulnar collateral ligament.

Sandoval underwent an MRI exam on Saturday and sought multiple opinions, but it was determined he’ll need season-ending surgery. He said he’s not sure the exact nature of the operation, but it’ll be some sort of Tommy John surgery to repair his UCL and he’ll be out at least a year -- possibly until 2026. He is under team control through ‘26, but the Angels could look to non-tender him this offseason or possibly extend his contract given the lengthy rehab process.

"It sucks, there’s no other way to put it,” Sandoval said. “I love being out there on the field and playing. It’s just unfortunate. I’m going to have surgery as soon as possible. I’m still not sure [the exact surgery], but I’m weighing my options."

Sandoval, 27, is one of the club’s longest-tenured players, making his debut in 2019 and becoming a mainstay in the rotation (outside of dealing with a season-ending back injury in mid-August of 2021). He posted a 2.91 ERA in 27 starts in 2022 and a 4.11 ERA in 28 starts last year while part of a six-man rotation, results that helped him earn the nod as the club's Opening Day starter this season.

He got off to a slow start with a 6.33 ERA in six starts in March/April, but pitched better over his last 10 starts with a 4.44 ERA and 53 strikeouts in 52 2/3 innings. He developed a sweeper that seemed to complement his pitch mix well.

Manager Ron Washington said it was difficult timing to lose Sandoval just as he started to get it going.

"It is tough for everyone, especially him because he was starting to really, really compete and then something like this happened,” Washington said. “You can't control it. But now we know he's got to get it fixed. We just got to continue to move on. I just told him the best of luck, and that I love him. There’s not much more I can say."

Sandoval said he’s tried to process the injury over the last few days, but that it hasn’t fully sunk in just yet. He knows it’s a long road to recovery but also is aware that it’s a common injury for pitchers in the modern game.

"It kind of comes in waves,” Sandoval said. “It’s just a long recovery process. It sucks. But I’m going to do what I can to get stronger."

With Sandoval out of the rotation for the rest of the year, the Angels will take a look at their options in both the short term and the long term. They need starters for Wednesday and Thursday or Friday, depending on when they start Zach Plesac, who joined the rotation last week and allowed nine runs in 9 1/3 innings over two starts.

Lefty Reid Detmers is still working on things at Triple-A Salt Lake but has pitched better recently, while right-hander Chase Silseth is likely to get another rehab start at Triple-A because of his recent struggles. Right-hander Davis Daniel is on the 40-man roster and appears to be a likely short-term solution. Right-hander José Soriano is expected to return in early July after dealing with an abdomen infection.

With all of this in mind, Washington said the Angels are "still talking about" figuring out a plan for who will start on Wednesday against Oakland.

Without Sandoval's services, the Angels will look to Griffin Canning to provide solid innings -- which he did on Monday, sailing through seven frames for the first time this season, limiting Oakland to five hits and one run, striking out five.

Like Sandoval, Canning has turned it around after a slow start, posting a 3.38 ERA over his last 10 starts dating back to May 1.

Canning, who has also been with the club since 2019, has known Sandoval since they competed against each other in high school nearby in Orange County, was disheartened to hear the news about his close friend.

"He’s a leader in this clubhouse,” Canning said. “There's a lot of energy he brings in the dugout day in and day out, so it's gonna hurt. But he’ll be around, so that’ll be nice to have him around."