Uehara said he first felt something during Wednesday's 30-pitch outing in Texas, and although nothing is official, the right-hander could be facing another trip to the disabled list.
Uehara hasn't pitched since Wednesday, leaving an already-short O's bullpen further depleted. With Friday's start of Interleague play, reliever Alberto Castillo was optioned back to Triple-A following Thursday's game to give the team another position player.
Orioles manager Dave Trembley said getting another arm and moving Uehara to the DL is a consideration, and that he's been in close contact with head athletic trainer Richie Bancells and president of baseball operations Andy MacPhail in evaluating the situation.
"[Uehara] wasn't available at all," Trembley said following Saturday's 7-6 loss to the Nationals. "He didn't pick up a ball. I doubt very seriously he'll be available [Sunday] to pitch.
"I'm not making excuses or anything, but it throws the whole bullpen out of whack, and you're putting guys in situations where you're asking them to do a little bit more or less, or you go with another guy a little bit longer."
Saturday's starter Brad Bergesen was the third consecutive Orioles pitcher who was unable to make it out of the sixth inning, and with relievers Cla Meredith, Jason Berken and Will Ohman already overworked, Trembley opted to go with long man Mark Hendrickson to follow Bergesen in the sixth inning. Reliever Matt Albers, coming off Friday's 35-pitch outing, was the only reliever -- aside from de facto closer Alfredo Simon -- who Trembley could feasibly turn to.
With closer Mike Gonzalez and setup man Jim Johnson both on the DL, losing Uehara again would be a definite blow to the Baltimore bullpen. Since returning from a left hamstring strain on May 6, Uehara has pitched to a 1.80 ERA in six appearances, stranding all five inherited baserunners.
Through interpreter Jiwon Bang, Uehara said that the club hasn't discussed putting him back on the DL. But given that he hasn't been available in three days, he acknowledged it's something that needs to be addressed, "sooner rather than later."
When asked if he feels that it's seemingly one injury issue after another Uehara said, "Everything is my fault."
Brittany Ghiroli is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.