Must read article on catcher framing and strike zone variance

by t ball on Feb 16, 2011 2:52 PM CST

From BP, but not behind the paywall, a great article on some tendencies in strike zone variations and the value of catcher framing. It seems that umpires vary the strike zone a bit depending on how pitchers throw to different hitters, with one Ranger brought up as an example:

For example, Jason Kendall hangs over home plate and is among the batters with the highest hit-by-pitch rates. Nonetheless, his strike zone was shifted almost an inch inside relative to the average right-handed batter. On the other end of the spectrum, Nelson Cruz has a very upright stance that keeps him away from the plate, and he is near the low end on hit-by-pitch rates. However, his strike zone was shifted almost an inch outside relative to average. What could be causing this disparity?

You might know that Kendall displayed the last vestiges of a power stroke during final years of the Clinton administration, while Cruz had a slugging percentage of .555 over the last three years. Despite Kendal’s tendency to crowd the plate, pitchers are unafraid to come inside and over the plate to him, whereas low and away is the favorite spot for a hurler confronting Cruz.

The typical pitch location seen by the batter has a strong correlation to the horizontal shift in his strike zone. Batters who see more pitches on the outside edge also see their strike zone boundaries shift farther away on both the outside and inside edges of the plate. Batters who see more pitches on the inside edge see their strike zone boundaries shift toward the inside.

Perhaps not surprisingly, this jives with the theory that catchers and pitchers can influence the ump's zone if the pitcher is consistently hitting the catcher's target. The article found that Francisco Cervelli was able to coax a few more strike calls than Posada in games started by Vazquez.

The article also indicates that pitchers who throw more on the edges of the zone get a larger strike zone than pitchers who throw more strikes, but more strikes in the middle of the zone.

I suspect that most teams, including the Rangers, have some proprietary data on stuff like this. The Rangers place a high value on a catcher's work behind the plate (the stuff that fangraphs cannot measure and quantify) and this article shows why.

Some of this has been suggested and theorized for many years, but now the data is backing it up with details and nuances. There is a LOT more in the article, check it out.

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Comments

Mike Fast does great pitchFX work.

Just thought I’d throw that out there.

If a morning thread ends in "This thread was a beating," I need to learn to press shift-A.

by AsDevilsRun on Feb 16, 2011 3:16 PM CST reply actions 1 recs

Somewhat related....

was looking at C.J’s pitchfx data on texasleaguers yesterday….

Before the ASB…

After the ASB…

This is only against RHB on both of the charts. The first thing noticeably difference is C.J. did a better job of pitching on the outer half of the plate against RHB after the ASB. And it also looks like C.J. started to get more calls go his way after the ASB on borderline strikes on the outer half of the plate (SO/BB ratio in the first half was 1.49 and 2.32 in the second half). It will be interesting to see if this trend continues as C.J. develops a reputation as a starter who paints the corners. Also there are some obvious missed calls on the inside half of the plate after the ASB.

It would be fascinating to to look at called strikes and balls broken up by the catcher behind the plate while C.J. was pitching since he did really well in a SSS with Teagarden as the catcher. Was Teagarden doing a better job of framing C.J’s pitches, was it randomness or was it something else?

by coolaid on Feb 16, 2011 4:09 PM CST reply actions

Few more tidbits on C.J....

BABIP before the ASB: .246
BABIP after the ASB: .294

SwStr%: 6.7% (league average is 8.5%)

by coolaid on Feb 16, 2011 4:14 PM CST up reply actions

I wonder how much of this was the Lee effect?

by bigsteve on Feb 16, 2011 5:23 PM CST up reply actions

or the Molina vs. Treanor vs. the field effect

What if something happens?!?
What could happen to an Old Fashioned?

by t ball on Feb 16, 2011 5:49 PM CST up reply actions

From the older studies on catcher framing linked in the article

Cliff Lee was net negative in terms of getting strikes called in 2008-2009.

Bengie was above average one year and below average in another in catcher framing/getting extra strikes called
Torrealba is consistently above average
Napoli is consistently below average
Laird was one of the worst in the league in both years.

As Mike Fast pointed out in the article, a large portion of these studies on catcher framing was polluted by the pitcher’s tendencies, so it’s hard to say how reliable they may be.

by Telegraph on Feb 16, 2011 5:58 PM CST up reply actions

hard to say

yep, and I think extremely hard to say exactly how valuable, in terms of runs allowed, the catcher is vs. the pitcher vs. random variation.

But, I’m glad to see Torrealba as consistently above average. Every little bit helps.

What if something happens?!?
What could happen to an Old Fashioned?

by t ball on Feb 16, 2011 6:26 PM CST up reply actions

I guess what I meant was

After Lee got here CJ admittedly changed and learned a lot from Cliff. Lee taught CJ to trust his stuff and basically pound an area if you are hitting there. That jives with this data that umps will “extend” their strike zones if a pitcher is constantly throwing there.

After the ASB CJ started throwing more often to the lower outside corner to RHB.

by bigsteve on Feb 16, 2011 7:03 PM CST up reply actions