August 6, 2010

Umps Shrink Jeter's Strike Zone by 16%

That is the strike zone plot for the 12 pitches that Jonathan Papelbon threw to Derek Jeter in the bottom of the ninth on Friday night.

Pitches 1 and 12 -- not exactly on the corners -- were called balls by home plate umpire Bruce Dreckman. No wonder Papelbon was so angry.

Back in May, David Biderman of the Wall Street Journal looked at the at-bats of every current Yankees and Mets hitter over two seasons and found that the best players get extra assistance from the umpires.
Derek Jeter and David Wright, the most-adored players on their respective teams, have the most generous strike zones, while Brett Gardner, the least-experienced Yankee starter, gets the worst treatment on his team. Research physicist John Walsh used Pitch FX — a camera system in MLB stadiums that measures the speed and route of every pitch — to see how much bigger or smaller Mets and Yankees hitters' strike zones are compared with how big they should be based on their height and batting stance. A smaller strike zone is better for batters because it means umps are calling fewer strikes.

Mr. Walsh included more than 33,000 pitches in his sample, but warned that the difference in strike-zone size — Mr. Jeter's is 15.8% smaller than it should be while Mark Teixeira's is 14.4% smaller — might look different if another two years of pitches were included. An MLB spokesman declined to comment.

But not all the All-Stars get special treatment. Relative to his height, Alex Rodriguez has the third biggest strike zone among current Yankees starters, only smaller than Nick Johnson's and Mr. Gardner's. "He's rubbed some of the umpires the wrong way," says two-time Cy Young Award winner Bret Saberhagen.
This is fascinating stuff! I'd like to see this info for every MLB hitter and pitcher (or at least the Red Sox).

Are the beefs of chronic complainers like Kevin Youkilis or David Ortiz legit or do the umps squeeze them as punishment for their whining? The strike zone for Mariano Rivera often seems much wider than it is for other pitchers (as if he needs the help). But is it true? Looking at a ton of pitch FX data could answer that question.


Amy said...

That is fascinating. Sounds like someone could make a Ph.D. dissertation about this. The Psychology of Umpiring: Does Perception of a Batter's Skill and Attitude Affect An Umpire's Perception of the Strike Zone?

I bet someone would underwrite a grant for that research.

9casey said...

that box isn't right the last pitch to Jeter was on the outide corner not inside.

RedSoxDiehard said...


9casey said...

I just watched the ab again, and I am not sure that anything on the graph is correct...

unless I am looking at it wrong

matthew said...

@9casey -- maybe the box is from the batter's perspective, not the pitcher's like we get on TV?

allan said...

The box is from the ump's perspective, so CI would be standing on the left side.

Unknown said...

Regardless of the orientation, the last pitch to Jeter was on or just off the outside corner, and so the graph/system is worthless.

Michael Holloway said...

I think it would be interesting to apply the science of sabremetrics to umpiring through this technology. I know major league baseball does it in their on going struggle to influence the product on the field through the umpiring crews. A public accounting would be nice ,and worth while. The un-informed opinionating about this ump or that is annoying. Umps probably have good days and bad days just like the rest of us.

On Jeter's strike zone in that game, it reminds me of what an umpire is reported to have said to a young pitcher, There is the story about the young pitcher complaining about a pitch to Williams that the umpire called a ball. The umpire allegedly says, “Son, when the pitch is a strike, Mr. Williams will let you know.”