New York Yankees general manager Brian Cashman said closer Mariano Rivera informed him earlier this week that he is unsure if he will play again or retire.

Cashman told ESPN New York that on Tuesday he and Rivera had a conversation in which Rivera said he does not know yet if he will return for a 19th season.

"He wasn't certain on what he is going to do," Cashman said.

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.

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 major league 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.