Monday, January 24, 2011
The Meaning of UZR
I recognize that determining a players defensive skills is a difficult chore. We know that the amount of errors committed doesn’t tell an accurate picture all the time of a players defensive skill. How many balls did a statue (Eric Karros comes to mind) never get to, thus he didn’t commit an error. Other defensive miscues such as missing a cut off man, failing to cover a base, bad reads and jumps to balls, and various mental errors can’t be quantified easily in the field.
I have to admit, the Ultimate Zone Rating (UZR) Statistic was something I wasn’t too familiar with. I had to do some research on it to get a feel for it. It’s a complicated formula that divides the field into 78 zones. You figure out the number of balls in play in each zone and then number of balls in which plays are made to determine a baseline average for fielders of each position. Then you compare that baseline average to the actual performance of a particular player. If he gets to less balls than the baseline average, his rating is in the negative and if he gets to more, then it is a positive rating.
So UZR is a stat that determines coverage of the field and the value a player has in getting to balls in the general area of his position. The UZR does a commendable job at determining a players defensive value by measuring his coverage of the field when compared to his peers. And in that statistic, Matt Kemp’s 2010 performance was absolutely horrid. To put it in perspective, the next to worse outfielder in UZR rating was almost twice as good as Kemp.
A UZR of 0.00 equals the positional average. So as a player you want a UZR in the positive territory. And Kemp had a 2009 UZR of +3.9 during that Gold Glove award winning year. His drop in 2010 of -24.0 is not only horrendous, it’s a historic deterioration. According to UZR, Kemp was 7 times worse the fielder than he was the previous year.
So why all this attention to UZR? Well, I looked into it because the MLB network and Larry Bowa are talking about it.
I understand Larry Bowa probably has an axe to grind since he was not renewed to the Dodger coaching staff. Mattingly apparently wanted him back, but word is that Colletti disapproved his rehiring. Bowa's comments on the MLB network Hot Stove show have a tinge of a rancorous tone to them. Last Friday’s comments were again particularly negative towards his favorite target, Matt Kemp. But in all fairness to Bowa, they probably were not too far off in terms of accuracy.
We all know it, Matt Kemp regressed defensively last season in unspectacular form. While the network proceeded to show footage of a number of fielding errors by Kemp. Bowa commented about the Dodgers and then Matt Kemp. Here is how that conversation went:
Greg Amsinger: “What changes do the Dodgers need to make if they’re going to be more competitive in the N.L. West?”
Larry Bowa: “Well obviously they’ve helped their pitching staff. They’ve picked up a couple of starting pitchers. But I think the one area that stood out last year. I personally, this is my own opinion, I think Matt Kemp has got to go to one of the corners. Because you have three guys in the rotation that are fly ball pitchers, and if you look at the National League West, Center Field is huge in every ball park. And you can’t let fly balls drop or get bad jumps on fly balls. So I think it is important to move him to the corner. On the other hand, you’re going to be sacrificing some offense. Obviously do the Dodgers have enough offense, to move him to one of the corners? Are they going to use Gwynn in center field or do they go the other way, keep Kemp in center field and you have Gibbons and Thames maybe to platoon in left field. It’s going to be up to the manager which decision he wants to make.
They then post this graphic on the screen:
Amsinger: “This is not a good stat for Matt Kemp in case you’re wondering. Zone rating, and that’s his number...the worst in all of baseball among center fielders. Here are the parks you’re talking about in the N.L. West,”
(they show a graphic of the dimensions of each NL West ballpark)
“...and this is your view, what you saw as a third base coach. There’s a lot of room to roam in Dodger Stadium and all the other ball parks.”
Bowa: “It’s unbelievable, Colorado, Arizona, San Francisco, San Diego, and you’re getting a lot of balls that should be caught that are dropping in or going to the wall. And for some reason, I don’t know if it was his concentration last year or it was just an off year, he was just a completely different player than he was two years ago. Maybe with a new year, he might go back to his old form, but last year, there were a lot of deficiencies in him playing center field.”
So obviously this entire segment was pre-planned. They had graphics of each ballpark, video footage of Matt Kemp errors, and zone rating stats all lined up for now what appears to be Bowa’s weekly attack on Kemp.
We all witnessed it last year. Matt Kemp played an awful center field. From 2009 Gold glove winner to the worst center fielder in the game...that’s what they are saying. I’m hoping that all this motivates Kemp to shut up the wonks that are so quick to criticize his 2010 performance.