Here's a feature on Luke Gregerson that leads with the claim that he might be the best setup man ever. To the Play Index!

Gregerson has 16 saves in his career of 363 games (347 innings) with a 126 ERA+. So here's what I searched for: pitchers with at least 250 innings, at least 90 percent of their games in relief, an ERA+ of 115 or better, and saves in fewer than 10 percent of their games. I found 81 pitchers. Here's a partial list:

Here's the whole list. (And thanks again to the SweetSpot for letting us use the Play Index.)

Other names you may recognize ahead of Gregerson include Craig Breslow (6th in ERA+), Eric O'Flaherty (8th), Chad Bradford (12th), Jim Corsi (16th), Kiko Calero (17th), and Ricardo Rincon (27th).

Gregerson isn't run-of-the-mill, by any means, and David Robertson will disappear from this list probably this year or next by virtue of the saves he's about to compile for the Yankees, but regardless of who the greatest setup man of all time is, I'm comfortable declaring it not to be Luke Gregerson.