Although it is still "probable" Mariano Rivera will pitch for the New York Yankees next season, the man considered the greatest closer of all time is having second thoughts about possibly retiring, sources tell ESPN New York. After he crumbled to the turf and tore his ACL in Kansas City in early May, Rivera vowed he would return in 2013. "I'm coming back," an emotional Rivera said in Kansas City a day after the injury. "Put it down. Write it down in big letters. I ain't going down like this." Now, with his 43rd birthday next month and as he's worked very hard during his rehab to return, Rivera has the familiar tug that he has carried for many years of possibly wanting to stay home with his family and call it a career. Rivera has yet to inform the Yankees of his final intentions, according to sources. In the past, Rivera also has emphasized that he expects to leave the game as an elite player. If he has doubts that he will retain his skill level, that also could tilt him to call it a career with the most saves (608) in MLB history and five World Series rings. The negotiations for a new contract also could be a bit complicated. Rivera made $15 million last season, but even with the front office's utmost respect for him, it is unclear what it will offer him considering he would be returning after a season in which he pitched in only nine games.