Injury Sidelines Rivera

New York Yankee closer Mariano Rivera is expected to open the regular season on the disabled list because of an injured right groin.

Yankee General Manager Brian Cashman said Tuesday there is no timetable for Rivera’s return but that players typically need three weeks to recover from groin problems.

Rivera felt discomfort Monday night while making his final pitch in the ninth, an inning-ending double play grounder by Travis Chapman in Detroit’s 4-2 win.

Rivera spent time on the disabled list last June because of a strain in the same area. He exercised Tuesday but is not throwing a ball.

Rivera was also on the DL last season because of a shoulder injury. He had been dominating this spring, giving up one unearned run and striking out 12 in 10 1/3 innings.

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Oakland Athletic center fielder Chris Singleton may miss the season opener next Tuesday against the Seattle Mariners.

Singleton, who hasn’t played since March 14, is recovering from having cysts removed from his thyroid last weekend in San Francisco. He has also been troubled by tightness in his right hamstring.

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Boston Red Sox relief pitcher Matt White’s back injury is more serious than first believed and he could start the season on the disabled list.... The Philadelphia Phillies acquired outfielder Wendell Magee from the Cleveland Indians for a player to be named.... The Kansas City Royals purchased the contract of outfielder Benny Agbayani from the Cincinnati Reds.... The San Diego Padres claimed utility infielder Lou Merloni off waivers from the Boston Red Sox.... The Milwaukee Brewers traded infielder Manny Alexander to the Texas Rangers for future considerations.... The Detroit Tigers reassigned pitcher Steve Avery to their minor league camp.... Infielder Juan Castro was put on the 15-day disabled list because of a sore knee, getting the Cincinnati Reds down to the 25-man roster limit.