NEW YORK (WFAN) – Yankees closer Mariano Rivera informed reporters on Wednesday that he had a blood clot in his right calf and has received treatment for it.

The treatment for the blood clot was the reliever’s “complication” that doctors revealed they encountered when examining Rivera on Monday, WFAN’s Sweeny Murti reported. The clot was found during the closer’s exam on Monday, and the five-time World Series champion is now on blood thinners. It isn’t clear whether the 42 year old’s knee injury had anything to do with the finding.

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Rivera was shagging fly balls last Thursday night before the Yankees’ loss in Kansas City — as he always does — when he collapsed in a heap on the warning track, grimacing in pain and rubbing his right knee.  Baseball’s saves leader was carted off the field, helped into the clubhouse and sent for an MRI.

After the game, manager Joe Girardi delivered the stunning news that the right-hander had torn his ACL. The injury ended Rivera’s season.

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Rivera was told to strengthen his knee before undergoing surgery to repair his ACL, Murti said, so at this time there is no date set for surgery.

The 12-time All-Star announced last week that he plans to play in 2013 following the rehabilitation process.

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Do you have any doubt that Rivera will be the Rivera of old when he returns to the mound in 2013? Offer your thoughts and comments below…