Afternoon Baseball

He's in the midst of his best season ever, at age 35. He has 30 saves (all in a row) in 32 opportunities with a 0.92 ERA. 9.92 K/9, which is his best rate since becoming a closer. Batters are hitting .149 against him, which is 63 points below his career average. Their OPS is .401 versus his career .557 OPS allowed.

Where does he rank career-wise, however?
First, he's one save away from tying Jeff Reardon for 5th all time at 367. Taking the top 5 in saves, plus Rollie Fingers (8th), John Wetteland (9th) and past standardbearers Goose Gossage and Bruce Sutter, let's look at their numbers...
A chart and lots of stats...Astericks mean data is only through the end of 2004
Name Saves ERA ERA+ 30-SV 40-SV Last 30SV K/9 H/9
L. Smith 478 3.03 132 10 3 age 37 8.73 7.91
J. Franco 424 2.89 139* 8 0 age 37 7.04 8.41
T. Hoffman 422 2.75 148* 9* 7* age 36* 10.07 6.78
D. Eckersley 390 3.5 119 8 4 age 42 6.58 8.43
J. Reardon 367 3.16 121 7 3 age 36 6.97 8.74
M. Rivera 366 2.34 190* 8 5* age 35 8.13 7
R. Fingers 341 2.9 119 2 0 age 31 6.4 7.8
J. Wetteland 330 2.93 148 8 4 age 33 9.46 7.25
G. Gossage 310 3.01 126 2 0 age 30 7.47 7.45
B. Sutter 300 2.83 136 4 1 age 31 7.43 7.59

Now...gone immediately is Eckersley, with an asterick. He was supremely dominating in his 1988-93 run, and is the only one to pitch effectively in his 40s, but he lost years being a starter and has both the worst K/9 ratio and the second-highest H/9 ratio. Plus the worst ERA and ERA+.
Rollie Fingers (and in some ways Gossage) is clearly the best of an extinct pitcher: the workhouse multiple inning closer. 1701 innings, which is just incredible. But he was not a closer in the sense that we think of now.

Rivera fares well, even though there are arguments to be made for some of the others (Hoffman, especially, and if Wettleland had pitched past 33 he'd might still be adding to his totals). Mo is high-ranking in 30- and 40-save seasons, K/9 and H/9, has the best ERA and an ERA+ that blows away everyone. Add in the postseason success that is unparalled, and there's a real argument that we're watching the greatest closer ever. And at his peak.