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4/12/2014 12:05 A.M. ET

Koji day to day with right shoulder stiffness

With closer unavailable, Mujica tosses 1-2-3 ninth to notch first save

NEW YORK -- The Red Sox had to stay away from Koji Uehara in Friday night's 4-2 victory against the Yankees, as the star closer felt some tightness in his right shoulder during pregame activities.

"Just tightness before the game playing catch," Uehara said through an interpreter. "It's difficult to explain, but just tightness. Two years ago, when I was with Texas, I felt the same kind of tightness."

In that case, the injury lingered, and recurred, and Uehara missed extended time.

The Red Sox will do everything in their power to make sure that doesn't happen again. For now, the club will monitor his condition on a daily basis, starting with Saturday afternoon's game against the Yankees.

"I can't tell for sure," Uehara said of when he'll pitch again. "I'd like to be back as soon as possible."

Manager John Farrell didn't seem overly concerned about Uehara, hoping it was just a little nag.

"Based on what Koji has expressed as far as the stiffness, this doesn't seem to be a one-pitch injury type of thing," said Farrell. "He felt some stiffness and we want to stay away from him."

Uehara is 39 years old and has had some durability problems in his career. He stayed healthy all of last season.

Edward Mujica saved Friday's game, and he will close while Uehara is out.

"When I signed with this team, they told me, 'We're going to have a lot of opportunities in the bullpen.' The job I did last year, they said, 'Mujica can do the job if Koji goes down.' But everybody is ready to go to do whatever role," said Mujica.

Ian Browne is a reporter for MLB.com. Read his blog, Brownie Points, and follow him on Twitter @IanMBrowne. This story was not subject to the approval of Major League Baseball or its clubs.