Comments on: Theo, Ellsbury, and UZR

By: Joe R

Joe R — Mon, 08 Mar 2010 21:03:49 +0000

Also, the DER of Boston gives a 95% confidence interval of the combined UZR of Boston CF’s to be between -31 and 9. So, also, not a ton of information to gain from this equation, just the point that team DER IS reflective of a CF’s UZR.

By: dutchbrowncoat

dutchbrowncoat — Mon, 08 Mar 2010 20:30:42 +0000

there are flaws with uzr, but i think you make a weak argument. a hitter can hit .280 one year and then .300 the next and you would be hard-pressed to notice an “observable difference” that is only a 15 hit or so swing and over the course of a full season you probably won’t notice. it is probably the same way with uzr – a mix of small changes in skill with timing and luck.

By: Joe R

Joe R — Mon, 08 Mar 2010 15:20:41 +0000

I think most smart baseball people see the fantastic upside, but evident flaws, in Ellsbury’s defensive game. I use BJ Upton as another recent example, and now he’s very good.

My guess is Cameron sees about 80% of the time in CF, and Ellsbury the other 20%

By: Joe R

Joe R — Mon, 08 Mar 2010 15:10:08 +0000

Oh yeah, FWIW, I just ran 2009 team BABIP-against to 2009 team CF UZR and got this equation:

CF UZR = -647.9*BABIP + 193.8
t-slope: -3.2796
t-intercept: 3.2778

That obviously doesn’t completely damn Ellsbury, but it DOES show that team BABIP-against and UZR have a correlation at a positional level.

Which means it’s likely that Ellsbury was not all that good in 2009. UZR’s weird 1 year sample may be too hard on him, but it’s not like he was a gold glover out there.

By: okin15

okin15 — Sun, 07 Mar 2010 15:24:31 +0000

Am I right that UZR counts missed plays per run, rather than per play? It would seem that this could greatly magnify an outfielder’s UZR, because they’re more likely to give up tripples and doubles, especially if their weakness, as Ellsbury’s is, is in going backwards. There might have been 5 balls that he just missed, but which kill him in the stat because of the run value of the play.

By: Jason B

Jason B — Tue, 02 Mar 2010 16:20:01 +0000

To that extent that no one cares what a blowhard like Plaschke says (which I think is largely true), similarly no one cares what Big Jim from Little Rock says on a message board. Let’s not conflate our importance here. Just like in the MSM, there are a handful of influential voices here, and a LOT of noise.

By: Everett

Everett — Tue, 02 Mar 2010 15:51:37 +0000

This would actually be an interesting study. Take all AL East LF and CF (or perhaps only Boston LF & CF) and compare the difference between home UZR and road UZR. While each individual’s sample will be smaller, that might give a large enough sample to show some sort of pattern.