Months ago when Mariano Rivera injured his right knee in a pre-game Yankees practice fielding fly balls, I wrote that was it for him, that he was never coming back. Rivera insisted that he would rehab and return for the 2013 season. Overshadowed during the recent Giants-Tigers World Series was Rivera alerting team management that is really thinking about retirement now.

Baseball’s greatest closer, the all-time record-holder in saves with 608, had debated whether or not to return to a New York uniform for the 2012 season. He was feeling his age), feeling the pull of home, but decided to play one more season. Then he wrecked his knee and what should have been a marvelous farewell tour went down the tubes.

Rivera immediately announced that he would fight back from the injury and play again in 2013. Understandably, he did not want to go out on such a sour note. The next stop for the 18-year veteran from Panama is the Hall of Fame, whenever he retires, so his legacy is not going to be tarnished regardless. But greats want to go out on their terms. There was no real evidence of slippage in Rivera’s performance before 2012, so there was no reason to believe that 2012 was going to be anything but another dominating year out of the bullpen.

Rivera was determined to go out in style, but sometime between May and October some measure of doubt must have crept into his mind. Age is likely part of it. Rivera would be 43 in 2013, not exactly a prime age for a professional athlete. But if he hadn’t been injured we might not even be talking about that topic.

It was clear from the start that the torn ACL Rivera suffered in Kansas City was a serious injury, one that would wipe out his 2012 season with no hope of return. Rivera was all determination and feistiness at the time, bravely claiming he would definitely be back in pinstripes. What happened in-between isn’t clear.

Maybe once Rivera got away from the ballpark, away from his teammates and began spending more time with his family he realized he had lost the hunger to keep going. Or maybe once he began rehabbing his knee the effort seemed to be too hard or too much. Rehab is brutal for the most single-minded and focused athlete. Maybe doubts seeped in and weakened Rivera’s determination to follow through day in and day out with mind-numblingly repetitive exercises.

About a week ago Rivera caucused with Yankees general manager Brian Cashman to let him know he might not be coming back. That was the first hint that Rivera has wavered from his declaration of return. That represents a major about face from post-injury statement: “Put it down. Write it down in big letters. I ain’t going down like this.”

Put it down: Rivera ain’t coming back. Maybe he can’t physically. Maybe he can’t regain the mental sharpness necessary. Rivera wouldn’t be talking about this with Cashman if nothing had changed and he was still on track to be ready, willing and able to participate in spring training. As the saves record-holder, as the owner of five World Series rings, Rivera would have to be highly motivated by other considerations to play one more year. If he only wanted to play another season to prove he can, he has earned that right. If he only wanted to play another season because he loves baseball, more power to him.

What I’m sensing is a bit of an internal tug-of-war. In theory Rivera might like to play again, but his age, his injury, his rehab efforts all tell him that a just-0ne-more-year approach is too complicated, and that it is time to let it go. I would love to see Rivera pitch another season, but I just don’t think he will.