Tuesday, November 13, 2012
A Hardball Times article suggested using WPA - WPA/LI as a measure of bullpen performance that would be useful in assessing bullpen management. WPA is the acronym for Wins Probability Added. This is calculated as the difference in win expectancy before and after an event. LI is the Leverage Index. It is a measurement of how consequential a specific scenario is based on the inning, outs, score, baserunners, and baserunner position. By using the two statistics in concert, you arguably have a measure that gives you a context neutral wins added metric.
WPA WPA/LI WPA - WPA/LI
Bob Melvin 3.75 0.83 2.92
Bruce Bochy 2.98 0.13 2.84
Joe Giraldi 7.37 4.88 2.49
Joe Girardi makes the top three, which confirms my belief that he manages his bullpen about as well as anyone in baseball and has done so since he’s come to the Yankees. I mean, the man got useful innings from Jose Veras.
Previous entry: Hardball Talk: The Yankees are interested in Mike Napoli