The muscles help stabilize the hip and leg while throwing.
Ryu had an MRI after leaving Wednesday’s loss to the
"I don't think anyone at this point feels like he's not coming back." Mattingly said. "We feel pretty good about, there's no tear in his elbow or anything like that. This is a muscle strain, it's going to heal, and he's going to be back."
Ryu said he's never suffered this injury before, but that there's "no doubt" that he will return this season.
"I was pushing off and then planting my foot and trying to catch my balance," Ryu said through an interpreter. "That's when I felt it."
There is still uncertainty. Not many major league pitchers pull the muscle that Ryu did, so it's hard to know how quick the recovery process will be.
"We'll probably know a lot more in three, four, five days, what he's going to be able to do," Mattingly said. "This is not an injury they've seen a whole lot of, there haven't been a bunch of guys with this that they see. The timetable will be determined kind of how he goes."
He was 5-13 with a 4.35 earned-run average for the Twins before being traded, and was slated to come out of the bullpen and spot-start when needed.
The Dodgers didn't expect those spot starts to come this quickly, but with Ryu out, they don't have much other choice.
Mattingly said the team doesn't have a plan for the rotation next week, mostly because the Dodgers have three off days in their next 14 days. This gives Mattingly the flexibility to shuffle the rotation a bit, and lessens the sting of missing Ryu, who is 13-6 with a 3.28 ERA.
"I just think he's a quality starter every time he goes out there," Mattingly said. "He gives you a good chance to win, and that's just not easy to find. I think we're going to miss that."
The Dodgers also called up right-hander Pedro Baez from Triple-A Albuquerque on Friday.