OAKLAND -- The Mariners announced that left-hander Robbie Ray underwent Tommy John surgery on Wednesday, in addition to the flexor tendon repair that was previously expected. He had already been ruled out for the remainder of the 2023 season, but the additional procedure means he's now likely to miss the beginning of '24 as well.

Dr. Keith Meister, the director of sports medicine at Arlington-based Texas Metroplex Institute for Sports Medicine and the Rangers' team physician, performed both procedures.

Manager Scott Servais said the news that Ray needed surgery to reconstruct his UCL was in line with his expectations.

"Obviously, he's got a long road ahead of him," Servais said. "The rehab and those situations can be challenging, but if anybody's going to come through strong, it'll be Robbie Ray."

Ray sustained the injury to his throwing arm in his first start of 2023 and was placed on the 15-day injured list the next day. It was determined that Ray would need season-ending surgery to repair a left flexor strain after a consultation on April 24, though there had been no public mention of Tommy John surgery up to that point.

"He was in good spirits, as good as can be when you go through something like that," said Servais, who had FaceTimed with Ray ahead of Wednesday's game in Oakland. "Hopefully he'll come back stronger than ever."

Ray's rehabilitation will mainly take place at the Mariners' Spring Training facility in Peoria, Ariz. Tommy John surgery typically requires a recovery period of 12 to 18 months, meaning he is unlikely to be ready by the beginning of Spring Training in 2024.

"He's a key guy in our clubhouse," Servais said. "Not just what he does on the mound on the day he pitches, but what he adds. We're going to miss him. … He's got to do what's best for him and his family and his arm to get it back healthy and get going again."

Ray is in the second season of a five-year, $115 million contract, which includes an opt-out after the 2024 season. Also of note is that Ray's pact with Seattle does not include any protection for the team in the case of Tommy John surgery. When the Mariners extended Luis Castillo nine months after signing Ray, they included a unique club option that would only be activated if Castillo required UCL reconstruction.

Ray's absence has long-term ramifications for the Mariners' rotation, particularly for top pitching prospect Bryce Miller. Miller dazzled in his debut on Tuesday in Oakland and could hold the edge for the No. 5 starter role, but he'll have to prove he can hold his own in the Majors with Ray out longer than previously expected.

Seattle's farm system also has a number of arms on the rise who could factor into the big league rotation picture, including Emerson Hancock (the club's No. 4 prospect per MLB Pipeline), Bryan Woo (No. 6) and Prelander Berroa (No. 14) at Double-A Arkansas and Taylor Dollard (No. 9) at Triple-A Tacoma.