BALTIMORE — Orioles pitcher Koji Uehara will be sidelined roughly two months after an examination of his ailing right elbow revealed a partial tear of the flexor tendon.

Uehara, the first Japanese-born player in Orioles history, was placed on the 15-day disabled list Sunday. The injury was initially believed to be a strained elbow, but tests revealed the injury to be much worse.

Now it appears Uehara won't return until late August or early September.

"Surgery is not required," Orioles manager Dave Trembley said Wednesday. "It's just a rest thing. Then, after the 3-5 weeks, he will have to start a throwing program. So obviously you're looking at 7-8 weeks total before he'd be in a game again if everything goes well."

The 34-year-old Uehara hasn't picked up a baseball since his last start, on June 23 against the Florida Marlins. He threw 76 pitches in that game before leaving with elbow soreness.

After starring for a decade in Japan, Uehara had endured a disappointing rookie season in the big leagues. He won his first two decisions but has since gone winless in 10 starts. He is 2-4 with a 4.05 ERA.

This is Uehara's second stint on the disabled list. A strained left hamstring kept him out from May 24-June 10, but this injury is far more serious.

"To tell the truth, I don't want to think about it," Uehara said through a translator. "I wasn't expecting it, not at all."

Uehara has pitched seven innings only once this season. He said the pain in his elbow did not become apparent until last week, but added, "It was on my mind, but not to the extent that I couldn't pitch."

Asked if Uehara might be sent to the bullpen upon his return, Trembley replied, "I'm sure that will be considered, but until somebody tells me that he's not a starting pitcher, that's what he is."

Uehara dismissed speculation he might be used as a reliever upon his return.

"I haven't thought about that at all," he said. "One day at a time."

Uehara's spot in the rotation has been filled by rookie David Hernandez, who's 1-2 with a 4.19 ERA in four appearances, including three starts.