The team made the announcement Wednesday before a game against the San Francisco Giants. The arthroscopic surgery will be performed by orthopedist Dr. Neal ElAttrache in Los Angeles. Manager Don Mattingly doesn't know a timetable for Ryu's recovery but said he did not believe it would be before the 2016 season.
The Dodgers expected to have a better idea after the procedure.
"Hyun-Jin has just been a quality starter, and pretty much every time he got the ball you knew that for the most part you're going to get a quality outing, keep you in the game against really any team," Mattingly said. "He had weapons for a lot of different hitters. Knowing that you're going to have to replace those innings, obviously not the ideal situation."
Ryu, who had been the team's projected No. 3 starter, has not pitched this season because of inflammation. Andrew Friedman, the Dodgers' president of baseball operations, had said Tuesday that surgery was an option given Ryu hasn't responded to prolonged rest.
The Dodgers are expected to look into trading for a starter.
"They're always looking to improve," Mattingly said. "It's not a great situation. It's just a test for our club as far as our depth. I think every team feels some measure of injury. Starting pitching is the toughest part. Over the course of a long season, as it starts getting hot in the summer, that's really when you find out what kind of pitchers you've got. We'll see as the summer goes."
Ryu was 14-7 with a 3.38 ERA last year. He signed a $36 million, six-year deal in December 2012.
Mattingly spoke to the pitcher in Los Angeles before surgery became the plan.
"His spirits seem to be pretty good," Mattingly said. "The progression wasn't getting better. That kind of tells the story."