ESPN seems to go crazy whenever Mariano Rivera blows a couple of saves, as he did last week. But here's why it's not a big deal.
For one, there is only one person who has gone a season as a team's major closer without blowing a save. That was Eric Gagne the year he won the Cy Young. And he was juiced.
Consistency is an important factor, but not the only factor. If it was, here's this year's NL MVP...Dan Uggla!
Mariano Rivera isn't doing that poorly. He's still saved the vast majority of opportunities he's had. Considering that Trevor Hoffman was considerably worse by this point his career (he limped to 600 saves; and was a middle reliever in his last season). Not to mention that loads of other marquee players have either retired long before 42, or by that time (Mays with the Mets, anyone?).
And if he's limping along, it's not like that will bring the Yankees to a screeching halt. The Yankees aren't built very much on pitching. For relievers, there's always Robertson, or Soriano, when they're healthy. For next season, they can (and probably will) buy Heath Bell or another innings-eater.
So, what do I think is going to happen? Rivera will finish the season with somewhere in the neighborhood of between 595 and 597 saves. The Yankees will buy another closer next season, and cut Rivera's appearances even more. But he'll still break the record in the first month or two of the season, make the All-Star team, sit out the All-Star Game, and then retire at the end of the season.