NEW YORK -- The New York Yankees activated closer Mariano Rivera from the 15-day disabled list and had him available in the bullpen for Thursday's game against the Kansas City Royals.

Reliever Mike Thurman was optioned to Triple-A Columbus to make room for Rivera.

Yankees manager Joe Torre said Rivera was ready to go.

"He gives the manager a sense of security,'' Torre said. "It's a little easier when you have that one guy who can stop the other team.''

Rivera was placed on the DL on July 26 because of a strained right shoulder. He pitched two scoreless innings in a rehabilitation start for the Yankees' Gulf Coast League team on Tuesday.

Rivera's shoulder tightened after he made just six pitches July 20 against Boston. An MRI exam revealed the strain, but no other damage. He was put on the DL retroactive to July 21.

The relief ace is 1-4 with a 3.06 ERA and 24 saves in 28 chances this season. He was on the disabled list from June 10-25 with a strained right groin.

Before this season, Rivera had been on the DL only once in his career.

Thurman was 1-0 with a 6.65 ERA for the Yankees. The right-hander made two starts and had six relief appearances.