When most relievers decide their baseball career is over, a team simply moves on to the next best guy they can find. Relievers are fungible and volatile, so the drop off isn't supposed to be significant to one from another. That has never been the case with Mariano Rivera. If relievers are fungible, he has been the exception to the rule. Even if the next guy to step into the closer role for the Yankees is very, very good, he won't come with the comfort that seeing number 42 jog out of the bullpen always provided. You'll have to hold your breath; you'll have to shift around in your seat. You'll have to experience the last frame of close games the way other fans have had to while we were all getting spoiled by the greatest there ever was.

It's beginning to sink in: this is Mariano Rivera's last year as a Yankee, and when 2014 rolls around, someone new will have to fill a position that no mortal reliever is capable of truly filling. That unenviable job will likely fall on David Robertson's shoulders barring a catastrophic injury or unexpected trade. We got a taste of life without Rivera in 2012, but it was almost a foregone conclusion that his absence was temporary. Mariano would be back and we'd all be able to return to our regularly scheduled ninth inning peace of mind. Next year, that feeling won't be a luxury we have. Rivera won't be returning. We have to deal with the bumps that will undoubtedly come without looking forward to when he returns to make everything less stressful. If people were uneasy with Robertson faltering before when they felt certain Rivera would return, just wait until he falters without that safety net in place. Rafael Soriano was more effective over a longer period of time in that spot, but he was still no Mo. His ninth innings often felt like a heart attack waiting to happen. Even when things were going ok, it just felt like he was on the verge of blowing the game. It never felt like that with Rivera, and it drove home the point of how difficult it is to do what Mo had always done seemingly effortlessly.