Aybar vs. Greinke
Marc Topkin of the St. Petersburg Times on July 18:
Manager Joe Maddon had his reasons for starting Willy Aybar on Saturday.
Aybar went 3 for 3 off Greinke.
On December 7, Tommy Rancel of DRaysBay published this exchange he had with Tampa Bay Rays coordinator of baseball operations James Click:
TR: what does Willy Aybar know about Zack Greinke?
Use pitchf/x data to create a projection system for individual batter/pitcher matchups.
I have none. The idea is overly ambitious, and I quickly realized I'm not the man for the job.
Chris Moore rather brilliantly ranked the best fastballs in baseball using five parameters: horizontal location, vertical location, velocity, vertical movement, and horizontal movement. Zack Greinke unsurprisingly came out on top.
Chris only looked at fastballs from right-handed pitchers against right-handed batters. If Chris were to have looked at RHP vs. LHB matchups, I’m sure Greinke would not have come out ahead, and instead Mariano Rivera would have topped the list. But what about RHPs against only Willy Aybar?
So I came up with a way to predict Aybar’s performance given certain pitch tendencies. For example, Aybar does best against slow fastballs around 90 MPH and he likes the ball down the middle. Plots to illustrate these points.
The Technical Details
My first data set consisted of all pitches Aybar faced from 2008 to July 18, 2009, and I tried to limit my sample further to only non-sidearming/knuckleballing RHPs. I ran a local regression to predict run values, weighing recent data the most heavily. My second data set contained all pitches from Greinke to LHBs over the same time span. I predicted my model onto that data set. Next, I regressed the expected run values for Aybar against Greinke toward the actual run values of Greinke vs. all LHBs he faced. I then regressed my projection even further to the the average performance of switch-hitting LHBs against RHPs, which I found to be around the league average .330 wOBA.
I predict Aybar to be precisely league average against Greinke.
My analysis gleans hardly any new insight into player projections. Aybar is below average against RHPs, but Greinke isn’t a world-beater himself against LHBs, having allowed an .824 OPS against LHBs in 2008.
I actually projected Aybar against all RHPs, and for what it's worth, I predict Aybar will do well against Pedro Martinez and poorly against Mariano Rivera. My model tells me Aybar will do surprisingly well against Roy Oswalt and surprisingly poorly against Armando Galarraga. It's not worth much.
The Loosely-Related Tim McCarver Quote
"I said it was Izturis who didn't get the bunt down last year. It was actually Manny Aybar. Excuse me, Erick Aybar, not his younger brother Manny who plays for Tampa Bay."