21 September 2011
In an excellent article by Mike Fast at Baseball Prospectus (free access), catchers are analyzed with PitchFX for their ability to get extra called strikes for their pitcher. The basic concept is as follows:
1) Using pitch location data from the PitchFX system from the years 2007-2011, Mike first established a standard strike zone by marking the boundaries where a pitch was called a strike at least 50% of the time.
RHB zone: -1.03 < px < 1.00 and (0.92 + batter_height*0.136) < pz < (2.60 + batter_height*0.136)
LHB zone: -1.20 < px < 0.81 and (0.35 + batter_height*0.229) < pz < (2.00 + batter_height*0.229)
2) He then counted the number of called balls and strikes tallied by each pitcher in the borderline zone to get a baseline number of "extra strikes" for each pitcher.
3) He then broke down the data for each pitcher-catcher combination, subtracting off the pitcher's baseline data.
4) Using Dan Turkenkopf's data on the value of switching ball/strike calls, the Runs Saved by each catcher was estimated.
Many more details are in the article, but the results showed that the best catchers for getting extra strikes for their pitchers were:
|Rank||Catcher||Total Runs 2007-2011|
Miguel Montero was ranked #7 among all catchers, and had a positive score for each of his seasons in the Majors. Based on this data, the best catchers can gain a win or two per year, just by their ability to get more strikes. How do they do this? The article has video of several catchers that shows some of the differences. Good catchers are more stable behind the plate, and make small movements to catch the ball. The bad catchers have a lot of body movement, and often dip their head and stab at the ball on outside pitches. Ryan Doumit, in particular, was shown to drop his head on low pitches, and umpires never gave him a called strike on those pitches.
There are obviously some questions raised because catchers are being compared to other catchers with the same pitcher. Thus, a catcher's teammates could make him look better or worse than he really is. But the data is fairly conclusive, showing consistency for catchers from year-to-year, even when they change teams. All in all, it's a fascinating article, and shows how a good catcher can take advantage of the "human element" of Major League umpires.
|Follow DV on Twitter||Buy DV D'Backs Tickets|