Ryu has spent the first six-plus weeks of the season on the disabled list and is expected to remain there for the entire year. Asked whether there was an outside chance Ryu could return to pitch this season, Manager Don Mattingly said, "I didn't get that feeling."
Now, with two of their top five starting pitchers lost for season, another problem has emerged for the once high-scoring Dodgers: They have stopped hitting.
They were shut out for the second consecutive game, falling to the San Francisco Giants, 4-0. They have scored two runs in their last four games and have lost five of their last seven games.
"It's going to happen," catcher Yasmani Grandal said. "It might as well happen now."
The Dodgers dropped to 0-5 at AT&T Park this season and their lead over the second-place Giants in the National League West was reduced to 2 1/2 games.
Mattingly downplayed concerns about the offense, which was limited to three hits in the first seven innings by right-hander Tim Lincecum.
"We're OK," he said.
Earlier in the day, the manager sounded far less certain about when Ryu might pitch again.
"I think we'll know a lot more once that's been completed," Mattingly said of the operation.
Ryu will be the second Dodgers starting pitcher to have a season-ending operation. Brandon McCarthy, who signed a four-year, $48-million contract over the off-season, underwent reconstructive elbow surgery last month.
"Hyun-Jin's just been a quality starter," Mattingly said. "Pretty much every time he got the ball, you were for the most part going to get a quality outing against really any team. He had weapons for a lot of different hitters. Knowing that you're going to have to replace those innings, obviously, is not the ideal situation."
Brandon Beachy is rehabiliting a surgically repaired elbow and could be ready to pitch some time next month. Until then, the Dodgers will likely continue using Mike Bolsinger and Carlos Frias as their fourth and fifth starters.
With Ryu and McCarthy sidelined, left-hander Brett Anderson has become the team's No. 3 pitcher.
Anderson started for the Dodgers on Wednesday, when he gave up three runs and six hits in 6 1/3 innings. Anderson didn't give up any runs until the sixth inning, when Buster Posey scored on a single to left field by Brandon Crawford.
While the Dodgers are encouraged by the recent form of Anderson, who gave up two runs or less in each of his previous three starts, they are also mindful of his workload.
Injuries have prevented Anderson from pitching 100 innings in any of his last four seasons. Last year, he pitched 52 2/3 innings, including 9 1/3 innings in the minor leagues.
Anderson could quadruple that innings count if he remains healthy for the entire season.
Pitching coach Rick Honeycutt said the Dodgers have tried to prevent Anderson and the others from fading late in the season by offering them extra days of rest between starts whenever possible.
By taking advantage of days off in their schedule, the Dodgers have started Anderson on regular four-days' rest only twice this season. His other five starts, including the one he made Wednesday, have been made on five-days' rest.
Clayton Kershaw and Zack Greinke have each started eight games, five each on five-days' rest.
Follow Dylan Hernandez on Twitter @dylanohernandez