The 25 Best Seasons by a Reliever in the Last 20 Years

Mariano Rivera? Francisco Rodriguez? Eric Gagne? Which pitcher will claim the top spot?

In the latter stages of a home improvement project, have you ever found yourself without the energy to put on the proper finishing touches? Did you bring in somebody to finish the caulking on the shower, or slap on that final coat of paint? After you made that call -- and after the whole thing was done to satisfaction -- you probably felt a great sense of relief.

The kind of relief a starting pitcher feels when his W is sealed by his bullpen ace.

All of which begs the question, over the past 20 years, which pitchers have provided the most value in relief? And how do we find the answer?

I'll tell you how: advanced analytics.

Thanks to FanGraphs, we have a plethora of advanced metrics to choose from, but the best form of measurement for our purposes is runs above replacement (RAR). RAR isn't far from wins above replacement (WAR), in that it also accounts for replacement level play, measuring runs rather than wins. Still, runs are applicable for us here, because preventing and saving runs are a key component to being a successful reliever. We broke ties utilizing RA9-Wins -- WAR per nine innings, calculated using runs allowed. (For information about other sabermetric with which you are unfamiliar, you can read up on them in the FanGraphs glossary.)

So here are the top 25 relief pitching seasons in the last 20 years, starting with number 25 and concluding with the reliever who provided the most value over the course of a single season.