The gold standard for relief pitching has been escalating for some time, but Mariano Rivera still has it both covered and defined.

With his 500th career save, Rivera has moved into a neighborhood so exclusive that there is only one other occupant. That would be Trevor Hoffman of the Milwaukee Brewers, whose revival has been so thorough this season that it seems 600 saves would not be out of the question for him. But let's consider one milestone at a time.

Mariano Rivera

The 500 saves denote something much more than personal success. In Rivera's case, those saves were core reasons for the success of the New York Yankees. Rivera was the closer for the last three Yankees World Series championship teams, and he was the closer for 11 straight Yankees teams that qualified for the postseason.

The coinciding success of closer and team was no coincidence. When former Yankees manager Joe Torre was once asked about his team's success on the road, he responded, "On the road with Mariano, we don't fear the bottom of the ninth."

Torre was correct, as usual. With Rivera, whether at home or on the road, the Yankees effectively shorten the game. The bottom of the ninth doesn't look like a perilous proposition when the opposition has to face one of the game's very best closers. A 92 percent rate of successful save opportunities would be a remarkable season, but Rivera has taken that record of excellence and extended it over an entire career.

In the sweep of baseball history, the role of closer is a relatively new development. The formula for determining what constituted a save, developed by the late, great baseball journalist Jerome Holtzman, has only been in effect for about four decades.

So judging the work of these specialists has been a work in progress. Witness the length of time it took for two pioneers of the closing role, Bruce Sutter and Goose Gossage, to be voted into the Hall of Fame. At the top of their careers, these two pitchers were nothing less than dominant, but it took Sutter 13 years on the ballot to be elected to the Hall, and it took Gossage nine. Clearly, the voters' consciousness of what defined greatness in relief pitching required some work.

It once appeared that perhaps 300 saves was going to be the mark of greatness. That number seems strikingly low now, but Sutter, Gossage and their contemporaries were often required to go two-plus innings to obtain their saves. The contemporary closer rarely has to record more than three outs for his night's work.

But Hoffman and Rivera have redefined what a Hall of Fame career as a closer might look like. Once Hoffman reached the 500-save mark in 2007, that became an obvious standard of greatness, but it was so great that it appeared to be very singular territory. But Rivera, even as he closes in on age 40, has not perceptibly slipped from his extraordinary standards.

500 ... and counting
With his 500th save -- all with the Yankees -- Mariano Rivera ranks second on the all-time list behind Trevor Hoffman, who recorded 554 of his saves with the Padres.
Rank
Pitcher
Saves
ERA
Most
First
1.T. Hoffman5712.76Padres1993
2.M. Rivera5002.31Yankees1996
3.L. Smith4783.03Cubs1981
4.J. Franco4242.89Mets1984
5.D. Eckersley3903.50A's1975
6.B. Wagner3852.40Astros1996
7.J. Reardon3673.16Expos1979
8.T. Percival3583.17Angels1995
9.R. Myers3473.19Cubs1987
10.R. Fingers3412.90A's1969
What separates these two careers from almost all others among closers is the astounding level of consistent performance, season after season. There are numerous relief pitchers who can put up a year or two of greatness, but then they fade. There are other relief pitchers who have stupendous seasons followed by seasons that are adequate or less, then they repeat the pattern. But the kind of consistent excellence exhibited by Hoffman and Rivera is the kind of thing that separates the great from the very good.

On the issue of who is the greatest closer of all time, Rivera has a built-in advantage over Hoffman. Rivera has had the opportunity to pitch as a closer in 11 postseasons. Hoffman, with the Padres for the vast majority of his career, has been in only four postseasons. Then again, Rivera hasn't exactly squandered these opportunities, recording 34 postseason saves and putting together a career postseason ERA of 0.77. People still talk about Game 7 of the 2001 World Series and the flare that beat Rivera and the Yanks not only because it was a thrilling Series but because Rivera losing a postseason save opportunity was an unknown phenomenon.

In that way Rivera's career as a closer is unmatched. Along the way, he has made the cut fastball a pitch for the ages, even though nobody else has duplicated his success with the pitch. His ticket to Cooperstown was punched long ago, but the 500th save puts a beautifully large and round number around his body of work. And along with the work of Hoffman, it sets the bar for greatness as a closer at a truly impressive and difficult to attain height.