TAMPA, Fla. -- New York Yankees closer Mariano Rivera hurt his right groin delivering a pitch Monday night and may not be ready for Opening Day.

	Rivera

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

"The initial reaction from our team physician is five-to-seven days and it should be resolved,'' Yankees general manager Brian Cashman said. "He did irritate the groin a little bit. He'll have to be shut down for a few days. The biggest thing will be how he feels tomorrow.''

Fantasy: Closer rankings Player News Fantasy Draft Kit

Rivera spent time on the disabled list last season for a groin strain in the same area.

"It's a little sore right now,'' Rivera said. "I didn't feel anything pop, which is good. Tomorrow I'll be able to tell you how severe.''

Rivera was also on the DL last season with a shoulder injury. He has been dominating this spring, allowing one unearned run and striking out 12 in 10 1/3 innings.

The Yankees open the regular season Monday at Toronto.