Baltimore manager Dave Trembley said that he'll have a few factors in mind, with Uehara's health and well-being standing chief among them. The right-hander is bothered by a sore left hamstring, and Trembley said that the Orioles will have to make a roster move if Uehara is expected to miss more than one start.
"I would say right now it is highly doubtful that Koji pitches on Thursday," said Trembley. "Whether or not he goes on the [disabled list], I'm not sure. But I would not expect that he's going to be ready to pitch on Thursday. I don't know what we're going to do yet. It's probably something we will decide after tomorrow's game."
The Orioles found themselves in a similar position for Tuesday's game. Baltimore released Adam Eaton last week and waited until the last possible moment to name Jason Berken as his replacement. Now, they find themselves waiting on word from Uehara's various conditioning drills to set their future plans.
Uehara was supposed to throw a sideline session Tuesday in preparation for his next start, but his ailing muscle held him to some light jogging and a brief session of playing catch. Uehara, who was bothered by a similar ailment in Spring Training, said that he hasn't even begun to contemplate when he can pitch again.
"My activity went well, but because I didn't pitch on the side today, that's something I have to determine," he said via interpreter Jiwon Bang. "I've had a long relationship [with the hamstring] for 10 years, so it's always there."
Uehara, who's 2-3 with a 4.09 ERA this season, went on to say that the hamstring injury is just about always present. It's something he's learned to deal with over time and something the Orioles knew about when they signed him. And for Trembley, it's yet another wild card in a rotation that's been hard to keep intact.
Baltimore lost Alfredo Simon to a season-ending injury after just two starts, tabbing Brad Bergesen as his replacement. Mark Hendrickson lost his starting gig due to ineffectiveness, and he was replaced by Rich Hill. And finally, the Orioles released Eaton in order to take a look at some younger prospects.
Jeremy Guthrie is the only sure thing in the rotation, giving Trembley pause with Uehara.
"I am concerned, because the guy has been a valuable pitcher," said Trembley. "He's given us quality starts, and you hate to lose that guy every five days or six days. But I told him, I'm certainly not going to put him out there when he's not 100 percent. I don't think that's what you do to him or anybody. ... We've played 45 games, and I want to be able to pitch in August and September. We have to do what we can to preserve that."
If Baltimore thinks Uehara can return after missing one start, then Hendrickson would be most likely to start on Thursday. But if the Orioles think Uehara's injury could linger, they'll likely dip down to Triple-A Norfolk. In that case, hard-throwing prospect David Hernandez would be the most likely candidate for a promotion.
And if that wasn't enough to consider, the Orioles have one more factor in play. Baltimore will need a roster spot for Luke Scott, who's likely to be activated from the disabled list on Wednesday. Scott could replace Uehara if the Orioles decide to send him to the disabled list, but he could also replace a position player.
"Tomorrow we'll probably have a better idea with Koji," said Trembley. "I know he's not going to pitch on Thursday, but I don't know what's going to happen overnight that we'll be able to say he's going to pitch in five more days. I mean, [pitching coach Rick Kranitz] and I talked to him at length this afternoon. He's going to have to tell us. If he's not able to pitch, we're going to have to do something to clear a roster spot -- one way or the other -- for Luke Scott."
Spencer Fordin is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.