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4/12/2014 1:56 P.M. ET

Mujica moves into closer's role on temporary basis

NEW YORK -- The injury to Koji Uehara puts Edward Mujica temporarily back in the closing role he became quite comfortable with over the course of the 2013 season, when he recorded 37 saves during the regular season for a Cardinals team on its way to a World Series matchup with the Red Sox.

Mujica is also intimately familiar with his current status in Boston: It's the second consecutive year he inherits the ninth-inning duties on the heels of an injury to the team's well-established closer early in the season. After projected Cardinals closer Jason Motte landed on the disabled list with a strained elbow just before Opening Day 2013, Mujica stepped in and excelled all year as St. Louis' closer before a rocky September that led Trevor Rosenthal to handle closing duties during the postseason.

"Everybody's ready in the bullpen to take care of business and everybody's prepared," Mujica said. "Everybody in the bullpen, we talked about that last night, just everybody being ready for whatever situation. Everybody prepares themselves to be out there."

With Uehara's recovery timetable uncertain, Mujica will be relied upon to step into the everyday closer's role and prove his value to the Red Sox after the 29-year-old right-hander signed on in the offseason merely as another piece in the defending champions' bullpen.

"One of the main reasons we signed him in the offseason was history last year showed us the need for multiple guys that can close games out in the event of the situation that arose last night," manager John Farrell said. "With a guy that saved 30-plus games and walks to the mound in the ninth inning very comfortable, we've got complete confidence in him."

Mujica's promotion leaves Farrell a little thinner on setup options, but he said on Saturday he felt comfortable mixing and matching as situations allow for the immediate future based on the early returns on the rest of the bullpen.

"Matchups are going to play a part of that," Farrell said. "[Chris Capuano's] emergence and our trust with him with both lefties and righties, Andrew Miller, who's got power stuff and can come in and close down an inning or shut down an inning by virtue of a strikeout. So we're going to mix and match as best we can and based on who's available on a given day."

Koji still unavailable; no decision if DL stint is needed

NEW YORK -- The Red Sox were without Koji Uehara for the second consecutive day as they faced the Yankees on Saturday afternoon, and after both the closer and manager John Farrell slow-played the significance of the shoulder tightness Uehara experienced while throwing before Friday's game, the team has elected not to rush its decision about a possible trip to the disabled list.

"He's unavailable today," said Farrell before Saturday's game. "We haven't gotten to the point of any roster move with him. We're still gathering information. We'll look to put him through a little bit of a throwing program tomorrow, and that's the next step, so right now still unavailable."

Uehara felt discomfort in his right shoulder during his regular pregame throwing program on Friday, and Farrell turned to offseason acquisition Edward Mujica to preserve a two-run lead in the ninth inning of the Red Sox's 4-2 win.

The 39-year-old Uehara told reporters the tightness felt similar to an injury that caused him to miss more than two months of action during the 2012 season with the Rangers. Uehara missed 66 games with a right lat strain and returned to make 17 appearances down the stretch that year, with 21 strikeouts and a 1.23 ERA in 14 2/3 innings.

"This is the first time we've had to deal with him being unavailable, so we've got to respect how he reacts to the discomfort that's there, the tightness that's there," Farrell said. "We also know that when he was in Texas, there was a setback during the time that he was on the DL, so to say that this is a direct comparison to two years ago is probably a little bit too early, but we'll take every precaution to get him back fully when he's able to return."

Farrell said that Uehara may attempt to resume his daily throwing program, which includes long toss from up to 200 feet, on Sunday afternoon. After capping off their four-game set in the Bronx on Sunday night, the Red Sox have a day off before starting a three-game set against the White Sox in Chicago. That extra day could help the team determine whether or not Uehara will need to be placed on the 15-day disabled list.

"It's another day available to us, and based on the information we get tomorrow, it gives us the possibility of him returning to Boston to be checked out," Farrell said. "That's not set in stone yet, but it is a possibility, and we're still gathering information along the way."

Farrell slides Pedroia into leadoff role

NEW YORK -- As Shane Victorino moved closer to returning from the right hamstring strain that landed him on the 15-day disabled list just before Opening Day with another round of batting practice on Saturday, manager John Farrell continued to mix and match to fill the holes in the outfield and at the top of the lineup.

Farrell rolled out a new combination of outfielders -- Mike Carp in left, Jackie Bradley Jr. in center and Daniel Nava in right -- for the Red Sox's third game of a four-game set against the Yankees, as well as a new leadoff man in Dustin Pedroia.

Pedroia becomes the fourth leadoff man used by the Red Sox this year, moving up in place of Jonny Gomes, who got the day off after jump-starting the offense at the top of the order with a solo shot in Friday's 4-2 win. After a red-hot start in which he hit safely in each of the first six games, Pedroia has just two hits in his last 22 at-bats entering Saturday.

"It's more about the overall performance in the leadoff spot," Farrell said. "It's also a chance for Dustin to focus on just getting on base. I think there's been times when [Pedroia] has expanded the strike zone a little bit and forced the issue some, so another opportunity to get him to see some pitches. This is now the fourth different guy we've had in the leadoff spot, so we're looking for a combination and a little bit of a spark at the top."

The shuffle has been even more pronounced in the outfield, where the Carp-Bradley-Nava starting alignment becomes the eighth different combination Boston has used in 12 games this year. After initially thinking he'd start 2014 in Triple-A, Bradley has welcomed the opportunity to redeem the slow start to his rookie season with a much stronger showing in the first two weeks of his second April in the big leagues. In 10 games, he has posted a .785 on-base-plus-slugging percentage, well ahead of last year's .617 mark.

"It's been one of those things where you come to the field and look, see where you're playing, if you're playing, and whatever happens, happens," Bradley said. "For me, that's how it is."

"I think more than anything, he's a little more confident right now at this point and time of the year than he was at any point during the [2013] regular season," Farrell said of Bradley. "Spring Training last year, yeah, he was kind of the new kid on the block, but he's played exceptional defense for us and is putting up quality at-bats."

Eric Single is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.