NEW YORK -- Yankees reliever Mariano Rivera has a mild muscle strain of the right shoulder and is listed as day to day, the club said Monday.

Two days after leaving a game against the Boston Red Sox, the All-Star closer had an MRI exam, which revealed the strain.

	Mariano Rivera

"It's just soreness, that's what it feels like,'' Rivera said Saturday. "It's not pain, that's what I keep saying. It just doesn't loosen up right away.''

He is 1-4 with a 3.06 ERA and 24 saves in 28 chances this season.

New York manager Joe Torre had said he won't use the right-hander for at least a few days regardless of what the tests reveal.

"We'll wait and see what the tests tell us tomorrow,'' Torre said. "It's a sensitive spot. It gets tight. He's not doing anything today. This is something that our trainer has dealt with before, which makes you think that it's not going to be something long term. However long it takes, it's going to take.''

Torre said before the game that left-hander Mike Stanton would assume the closer's role Sunday if needed. Stanton (4-1) entered in the eighth inning with the Yankees trailing and pitched two scoreless innings for the victory as New York rallied to beat Boston 9-8 for the second day in a row.

Rivera is 1-4 with a 3.06 ERA and 24 saves in 28 chances this season.

The Yankees led 6-3 when Rivera was summoned in the eighth inning Saturday with no outs and runners on second and third.

He struck out Manny Ramirez with a fastball, but allowed a two-run single to Jason Varitek. After the count went to 2-1 on Shea Hillenbrand, Torre and a trainer hurried from the dugout to the mound.

Following a brief discussion, Rivera was pulled after throwing only six pitches. The Yankees' career saves leader slowly walked back to the bench with his hands at his side.

New York won 9-8 in 11 innings.

Rivera was put on the DL for the second time in his career on June 10 because of a strained right groin. He returned on June 25.

Last Sunday in Cleveland, Rivera gave up a game-winning, two-out grand slam in the bottom of the ninth inning to Bill Selby. Rivera came back to earn saves Tuesday at Toronto and Thursday against Detroit.