The latest injury to strike the Dodgers is literally a pain in the rear.
While Ryu said he didn't think the injury was serious, he acknowledged he didn't know if he could take his next turn in the rotation.
"A little too early to tell," he said through an interpreter.
Manager Don Mattingly was also uncertain, saying, "I'd just be guessing."
Mattingly said he expected Ryu to undergo a MRI examination and visit team physician Neal ElAttrache after the Dodgers return to Los Angeles on Thursday night.
"It sounds like day to day at this point," Mattingly said.
"We're all hopeful, fingers crossed, that Hyun-Jin will make that next start because he's a huge part of our success and where we're headed," Ellis said.
Ryu is the clear-cut No. 3 starter in a rotation that includes two of the best pitchers in baseball, Clayton Kershaw and Zack Greinke.
Ryu was charged with three runs and six hits over 5 2/3 innings Tuesday night and absorbed the loss. Still, he is 13-6 with a 3.28 earned-run average. He won his previous four decisions and the Dodgers had won each of his last five starts.
Of the team's lead over the Giants, Ellis said, "I don't think we're at that cushion stage yet. We're still on the building phase."
The Dodgers have a day off Monday, meaning that if Ryu can't face the San Diego Padres at Dodger Stadium on Tuesday, Roberto Hernandez could replace him and pitch on regular four-days' rest. Another option would be to start recently acquired swingman Kevin Correia, who limited the Braves to one run over six innings in a spot start Monday.
The injury to Ryu came suddenly.
With the Dodgers trailing, 3-2, Ryu started the sixth inning by forcing Chris Johnson and Andrelton Simmons to ground out.
Up came B.J. Upton.
At some point in the nine-pitch at-bat, Ryu felt discomfort in his backside.
"I thought I could pitch out of it, but it kept getting worse and worse," he said.
Mattingly figured something was wrong.
"We saw a couple pitches where he looked a little bit funny," he said.
Mattingly recalled pitching coach Rick Honeycutt looking over at him and asking, "Is he all right?"
Upon walking Upton, Ryu called to the bench.
"I knew that's never a good thing," Ellis said.
Ryu was replaced by Jamey Wright.
Ryu said he regretted not calling sooner for the trainer. He said he was somewhat concerned about his condition because he had never previous sustained a similar injury.
Ryu was comforted by the fact that his discomfort was concentrated in his buttock and didn't extend into his hamstring. An examination by head trainer Stan Conte appeared to confirm what he felt.
"I don't think it's very serious right now," Ryu said.
The defeat was the Dodgers' first in six games against the Braves this season. The Dodgers swept the Braves at Dodger Stadium at the end of last month and won the first two games of the current series, which concludes Thursday.