But with Mo on the mend from a torn ACL, we are left with the reality that there is no such thing as the clear-cut shutdown closer upon which all other closers are judged.
"Not this year," said Indians closer Chris Perez. "You'd have to have a write-in contest."
Perez is one of three men leading the Majors with 11 saves, but he's blown a pair of opportunities and has an ERA of 3.95. Jonathan Papelbon, the Phillies' $50 million man, is the only guy with a track record anywhere near that of Rivera's, and he's 10-for-10 in save situations this season, but he obviously hasn't had as many opportunities as Philadelphia envisioned for him.
Arguably the two best closers in the game this year have been the Rays' Fernando Rodney and the Orioles' Jim Johnson, both of whom are a perfect 9-for-9 in save situations with miniscule ERAs -- and surprisingly so. The Braves' Craig Kimbrel has saved 11 of 12 with an ERA of 2.77. Fresh off saving Game 7 of the World Series, the Cardinals' Jason Motte is 6-for-7 with a .170 average against.
Those are your early-season candidates for the honor, but don't get too comfortable with any of the above, for this stuff is constantly evolving. It's a shame we'll remember Kimbrel's 2011 as much for his collapse on the final night against the Phillies as for his overall dominance (46 saves and 127 strikeouts in 77 innings). The Brewers' John Axford tied Kimbrel for the league lead with 46 saves last year, but has a 6.10 ERA this year. The Tigers' Jose Valverde was a perfect 49-for-49 last year. Now, he's 7-for-9 with a 4.60 ERA.
Basically, it's hard to trust anybody not named Rivera, for he was the one relative constant in an otherwise permutable profession -- one that has opened itself up to increased scrutiny due to the injuries and ineffectiveness pervading it.
Teams are converting just 65.4 percent of their save opportunities -- with just a 62 percent conversion rate in the National League. This sounds low, until you realize that in the last decade, the Major League-wide save percentage has never been lower than 64 percent and never higher than 69. It hasn't topped 70 percent since the late 1990s and hasn't hit 75 percent since the late '80s.
So in the quirky world of closing, we grade on a curve in which what smells like a D reads at least as a C.
But if anything stands out about the ninth-inning role in 2012, it's the remarkable turnover taking place. Twenty of the 30 closers from Opening Day 2011 were no longer filling the same role for the same club a year later. Dating back to the beginning of Spring Training, Rivera, Brian Wilson, Andrew Bailey, Joakim Soria, Ryan Madson, Drew Storen, Sergio Santos, Kyle Farnsworth and Huston Street have all been injured, while Heath Bell, Jordan Walden, Carlos Marmol, Mark Melancon, Javy Guerra and Grant Balfour have all, temporarily or otherwise, been demoted.
Total 2012 cost for those arms? Right around $70 million.
So, despite some obvious pre-arbitration exceptions, many clubs are investing ridiculous resources into a role that is unstable, even by professional sporting standards. And the injuries are proof positive that the glad-handing of ninth-inning arms hasn't made them any more durable.
"You throw till you blow," said Rangers closer Joe Nathan.
With that reality in mind, there has been a line of thought uttered increasingly often about the need to rethink the closer role and to groom relievers who can tolerate multiple innings routinely. Sports Illustrated's Tom Verducci wrote a thought-provoking piece on this very topic last month, pointing out how ineffective and inefficient the current system has become.
"Imagine if every team in the NFL used the same 3-4 defense," Verducci wrote. "That's essentially what is happening in baseball. Everybody runs their bullpen and their pitch-count policies the same way."
Some teams are a little more prone to take chances. The Rangers, for instance, have become less strict with pitch-count restrictions in the Minors, and they've turned Alexi Ogando into the rare power reliever who can provide multi-inning relief. But that doesn't mean they're going to revolutionize the way relievers are born and bred.
"As an industry," said Rangers general manager Jon Daniels, "we're probably a little too rigid with it. But I don't think it's as easy to just mix and match as some people make it out to be."
The high-90s hurler who comes in and tries to blow people away in the ninth is a product of the one-inning mentality.
"It's more violent for that one inning," Nathan said, "but that's the way people get it done. If they had to go two or three, guys might not throw as hard as they do. With this day and age and how the lineups are so deep, it probably wouldn't work out so well for closers to go out there and just try to pitch."
And those groomed to get the last three outs have more than just the opposing lineup on their mind.
Fans and sabermetricians are angered to no end by the fact that managers almost always shy away from using their closer -- conceivably, their best reliever -- in tie games on the road so that they can instead preserve them for a save situation that may or may not exist. But consider what the manager is up against with regard to that decision. If he turns to his closer at that point, he is robbing him of a potential save situation that could potentially be worth big bucks to him down the road -- in arbitration or free agency.
"They want the save," Perez said. "How any times do you see managers bring a closer in on the road? They don't do it."
Closers want saves, and setup men want holds, because that's what drives their bargaining power. So when a manager maneuvers his bullpen, he must account not just for the opposition but also for in-house ego.
And then, of course, there is the notion that once roles are established within a bullpen, relievers cling to the stability they provide, in terms of how they prepare, mentally and physically, for each outing.
"That's what people miss," Daniels said. "These guys are human beings, and there's a routine involved to knowing what your role is going to be. One of the reasons Ogando is so valuable is he can handle going in the fourth inning one night, if he has to, then get the save the next night, and he's fine with it."
That mentality is more rare than we'd like to admit. And rarer still is the ninth-inning arm so stable and so dependable that you can count on building a bullpen around it for years to come. Rivera was in a class all his own in that department.
There are some terrific, intimidating closers in the game today, and Papelbon qualifies as the elder statesman of the bunch. But in the costly and quirky world of closing, good luck getting consensus on the "best in baseball" question, now that Mo's on the mend.