LOS ANGELES -- Dodgers right-hander River Ryan has impressed over his first four Major League starts. But as he worked on another gem on Saturday at Dodger Stadium, Ryan’s night ended much sooner than expected, as he left the Dodgers’ 4-1 win over the Pirates in the fifth inning alongside a trainer.

Ryan, who’d allowed just four hits over 4 2/3 scoreless innings, was immediately seen shaking his right arm in discomfort, and the Dodgers later announced that he’d left with right forearm tightness.

After undergoing an MRI on Sunday, the Dodgers announced the rookie’s season will come to an end with a right elbow injury, and he was placed on the 15-day injured list. Dodgers manager Dave Roberts said the medical staff is still talking through what comes next, but didn’t rule out the possibility of Tommy John surgery.

“I don’t know the exact diagnosis, but his season is going to be over,” Roberts said. “I think they’re waiting on some other scans to figure out the exact course of action. Obviously right now, what I can say is his season is going to be over.”

Ryan said he started to feel discomfort in his right forearm in the third inning, but didn’t think too much of it. In between innings, Ryan worked on the forearm with a massage gun to keep it loose. But in the fifth, as he fired off a couple pitches to Michael A. Taylor, the coaching staff noticed Ryan wincing in pain.

“I definitely didn’t want to come out of the game,” Ryan said on Saturday. “I wanted to finish. But they saw me grimace a little bit on the mound, and they’re not going to take any chances. So they decided to call it then and there.”

Losing Ryan is the latest hit to a Dodgers team that has been decimated by injuries this season. In fact, a big reason Ryan made his Major League debut much earlier than expected -- and just two years after becoming a full-time pitcher -- is because the Dodgers have had 11 starters land on the injured list at least one time this season.

“It’s been challenging,” Roberts said. “Personally, I feel for each guy, because it’s their careers and I know how hard it is. Most recently with River and how disappointed he is, but it’s one of those things that there’s some sensitivity in the sense of feeling it, but also making the guys available feel like they’re the best options. I think they’ve done a really good job of picking up the pieces, and the guys who are available are giving us the best chance to win.”

In his first four starts, Ryan excelled, posting a 1.33 ERA. Ryan is also a big part of the Dodgers’ future in the rotation, as he is ranked the No. 4 prospect in their system, per MLB Pipeline.

With Ryan set to miss the rest of the season – and possibly beyond that – the Dodgers will turn to Walker Buehler to fill in that spot in the rotation. Buehler made three rehab starts with Triple-A Oklahoma City and is scheduled to pitch on Wednesday against the Brewers in Milwaukee.

If the Dodgers are in need of a sixth starter during tough stretches, they can also turn to Landon Knack, who was activated on Sunday to serve out of the bullpen, Bobby Miller, who continues to work through his mechanics in Oklahoma City, or Justin Wrobleski.

Though there are options, the Dodgers have definitely felt the crush of the injuries that have piled up over the last few seasons, especially in ‘24.

“I think that we clearly don’t have the answers to taking care of pitchers and keeping them healthy,” Roberts said. “I think the industry is doing the best they can to manage workload, manage pitch count, but clearly, we don’t have it nailed. … It’s just unfortunate, because a lot of great talent is on the IL.”