Valuation of defensive stats

[gunnarthor]

Hi all,

 

Last year, Eddie Rosario hit .290/.328/.507 118 OPS+ and it was worth 1.7 WAR. This year he's hitting .294/.333/.498 OPS+ 121 and is already at 3.9 WAR.

 

The main difference seems to be defense. Last year, his defense was worth -1.6 WAR, numbers that Josh WIllingham and Delmon Young would've been embarrassed to have. This year he's a positive. Kepler has slightly improved his defensive WAR as well. The main difference to me seems to be that Buxton isn't in CF. Years ago there were some articles that three good OFers are hard for the defensive stats to accurately measure so one is usually dinged. With Buxton playing so well last year in the OF, it seems like Rosario was perhaps unfairly undervalued.

 

Does anyone have more insight into defensive valuation in cases like this? Do we think Rosario has significantly improved this year or does Buxton's absence make it easier to value his contributions? 

 

[Vanimal46]

I think you hit the nail on the head. Buxton absorbed a ton of defensive value from Kepler and Rosario last year.

 

Rosario still makes bone headed decisions in the OF... Is it less than last year? Not sure.

[John Kelsey]

 

I think you hit the nail on the head. Buxton absorbed a ton of defensive value from Kepler and Rosario last year.

Rosario still makes bone headed decisions in the OF... Is it less than last year? Not sure.

 

He still makes those boneheaded plays but I think people forget how many of them he made last year, he's definitely been better this year.

[USAFChief]

[Brock Beauchamp]

Rosario has looked better this season but I firmly believe he was a victim of Buxton's greatness last season. I remember doing a comparison last year of some previous Tampa outfields and one outfielder seemed to take a hit every year, despite being a good or very good defender.

 

I don't know why it happens - I have a couple hypotheses - but have never seen an in-depth study done on the subject.

[Mike Sixel]

I think it is partly Buxton, and partly that OF get a handful of plays, maybe 10-20 or so, that can make or break their stats.....from year to year. Sometimes they'all all go right, and sometimes they'll all go wrong. But, having "watched" Rosario his whole career, I'm guessing it is also that the dude can make some interesting plays at times....which sometimes work, and sometimes don't.

[Doomtints]

Looking deeper at Baseball-Reference, it looks like Rosario is a disaster in CF and RF. He logged 149 innings at those positions last year and 32 this year. There's the difference. His metrics in LF are similar in 2017 and 2018.

 

If Rosario's numbers are dragged down due to his play in CF, this means Buxton isn't on the field to steal stats from him.

 

When Florimon was next to Dozier, Dozier's defensive numbers shined like they never have before or since. Dozier got a reputation of being a good defender from that one season alone, which is absurd when you look at it. I have a suspicion that good people around you make you look better, not worse, which has to be annoying to GMs during free agency. Apart from the eye test, there's just no way to know who is legit on defense and who isn't. Robbie Grossman, anyone?

 

Anyway ... don't be fooled ... Rosario is barely an average defender ... not an elite one. If he keeps hitting any ball thrown his way, who cares.

[TheLeviathan]

I think these stats still have a long way to go unfortunately.

[Brock Beauchamp]

 

I think these stats still have a long way to go unfortunately.

They definitely need some refinement and I think their job has only become harder with the popularity of the shift in recent years.