Yankees bullpen good, but not that good…

In 2010, collectively, the Yankees’ relief corps posted an impressive ERA of 3.47, which was, in the end, the third best mark in the American League (only the Rays, 3.33 ERA, and the Rangers, 3.38 ERA, were better). However, if we dig deeper and actually scrutinize the numbers using FIP – I mean, it’s never fun to just accept something as is – we see that the team’s bullpen was not as bulletproof as their sparkly ERA would suggest.

On the season, the Yankees’ relievers pitched to the tune of a 4.06 FIP. Of course, this is hardly a bad number, but, if we consider FIP as a better representation of performance when compared to ERA, then the Yankees didn’t have a top-3 AL relief staff. Instead, their bullpen was tied with the Angels for 8th best in the league. Also of note is that the Yankees had the second largest difference between ERA and FIP – 0.59 – across both leagues—not just the AL (only the Rangers posted a higher mark).

Explaining the difference between the two figures is fairly straightforward. For one, the Yankees, according to UZR, had a rather strong defensive season, with a collective UZR and UZR/150 of 19.7 and 2.5, respectively. Both figures stand as 5th best in the AL, indicating that the Yankee relievers likely benefited from the gloves behind them (for instance, consider that the Yankee outfield, comprised of Brett Gardner, Nick Swisher, and Curtis Granderson, was the second best defensive outfield in the AL, and that their bullpen had the 7th highest fly ball percentage). The Yankee bullpen’s FIP can also be explained through the always-interesting prism of luck, as the team’s bullpen posted the second lowest BABIP (.276), not just in the AL, but in the NL, as well.

So, there you have it—an interminable and meandering piece on why the Yankee bullpen was pretty good, but not nearly as good as ERA would have you believe. Defense and luck, the Yankees’ relievers thank you.

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