"I can't say there won't be the need that we use other guys, but where we are today, Koji will close out if we get in that situation tonight," Red Sox manager John Farrell said prior to Friday night's game against the Detroit Tigers. "I think we're very confident when he walks out to the mound. He's had success in closing opportunities, so there's not only an element of dependability but success in the past that we're turning to."
Uehara had 13 saves in 2010 with the Baltimore Orioles. He also had 32 saves while in Japan in 2007.
He had one save last year with the Texas Rangers, and has one this season for the Red Sox.
"I'm not going to change anything," Uehara said through a translator Friday. "I'll do my best about going on with my business."
In 30 innings pitched this season, Uehara has 42 strikeouts and just seven walks, including two intentional.
"We're staying internal right now," Farrell said. "I know [general manager] Ben [Cherington] is always on the lookout to improve the team within reason. So for the time being, we're staying with who we have."
The move comes after Bailey blew his third save in his past five tries Thursday night, giving up a two-run homer to Detroit's Jhonny Peralta in the bottom of the ninth of a 4-3 loss.
"It's just kind of giving me a little breather," Bailey said Friday. "It's understandable for sure. I wasn't doing the job, and I totally get it. One bad week doesn't necessarily make a bad year. The way I was throwing the ball at the beginning, then I missed some time, having a rough go at it right now. Doesn't mean it's been a bad year by any chance.
"I fully believe I'm the guy here to do that job. Right now, they're going to go with someone else for a little bit, but I don't think it's a permanent thing. Anything can happen, and I'm fully aware of that. I feel like this is my job. I've got confidence I'll be back in there. I've just got to throw the ball like I can."
Farrell will monitor Uehara closely as chances to save games arise.
Farrell's decision to go with Uehara was based mainly on his experience of closing out games before.
"I'm not saying there might [not] be an opportunity for Miller to be exposed to that," Farrell said. "If we got in a situation the other night, he was warming up and he probably was going to get [Andy] Dirks. There is no reluctance of going to him."
Farrell doesn't know when Bailey will move back into the closer's role, but has left open the door.
"I thought last night, despite the outcome, he was down in the zone better and used his breaking ball a little bit more, but it ends up in a two-run homer to walk it off for them," Farrell said. "He needs to regain some momentum and some confidence on his part, realize some positive results and carries that back into the ninth inning.
"Andrew is a stand-up guy. He recognizes fully and takes responsibility over the last five opportunities and realizes that change is here among us, but in his mind I think he remains a confident guy, knows he's talented and capable of pitching the ninth in the big leagues."
In Bailey's past five appearances, he has given up four homers and seven earned runs.
"I think we've got to get a couple of outings under his belt to reinforce his confidence and just be able to walk off the mound with a successful outing," Farrell said. "It's hard to script right now and in what situation that will be in."
The Red Sox also confirmed Friday that catcher David Ross is dealing with a concussion and will be out until at least July.
"He came away from (Thursday) with quite a bit of information with the tests he went through and he clearly has a concussion," Farrell said. "Results were evident in those tests."
Ross was examined Thursday in Pittsburgh by neuropsychologist Dr. Micky Collins, who is Major League Baseball's consultant on concussions.
"(The) recommendation was to basically shut down for a period of time," Farrell said. "He'll be away from the team and return home to Tallahassee [Fla.] until his next scheduled appointment with Dr. Collins, which is the first week of July."
Ross went on the disabled list on May 12 for concussion symptoms that sidelined him for 11 games. He was placed on the DL again on Tuesday.