Several of you asked for a bullpen version of the “best pitches in the rotation” post, and so here you go. Instead of just the 2011 season I’ve gone back and corralled the last two seasons worth of data for this post. The columns headed by “w” and “w/100″ are the pitch type’s linear weights (representing the total runs that a pitcher has saved using that pitch) and linear weights per 100 pitches (the amount of runs that pitcher saved with that pitch type for every 100 thrown), which provide some level of insight into a pitch’s relative level of effectiveness but should not be analyzed in isolation, as they are subject to the whims of both sequencing and BABIP. I’ve ranked the hurlers by their respective Whiff rates, as the ability to generate a swing-and-miss is probably the most transparent indication of pure stuff.
(Note: This post was researched and written prior to the release of the reclassified PITCHf/x data at Brooks Baseball — which I’ll be chiming in on next week — and the numbers are from TexasLeaguers.com and Fangraphs. Given that relievers typically have less variation in their repertoires than starters, I feel comfortable that the data presented below is mostly accurate.)
Rafael Soriano’s generated the highest whiff percentage on the four-seamer out of the six primary members of the Yankee bullpen, though that is probably partially propped up by his excellent 2010. As far as pitch type linear weights go, David Robertson’s four-seamer has been the most effective at 12 runs above average, while Cory Wade’s was most effective on a per-100-pitch basis, at 2.17 runs above average.
Without looking at the numbers I’d have assumed that Mariano Rivera would easily lead in cutter Whiff%, but he actually lags both Soriano and D-Rob. Of course, having even an 8.1% whiff rate on a pitch you throw 86% of the time is still absurd.
For all the crap Boone Logan gets, his slider’s actually pretty outstanding, generating a whiff nearly one out of every four times he throws it. Joba Chamberlain also has a big-boy slider, though at times (cough cough full count cough) he’s fallen a bit too in love with it, occasionally making it painfully predictable.
David Robertson has the best curveball in the ‘pen by a pretty substantial margin, though Cory Wade’s isn’t terrible. Joba’s had a decent amount of success with his curve though he throws it pretty infrequently.
It’s Cory Wade by a landslide here, though he wins by default as no one else in the ‘pen really throws a changeup. It hasn’t been an outstanding pitch by linear weights, but it was his bread-and-butter in a terrific season for the Yankees in 2011.