I looked on baseball reference. http://www.baseball-...-fielding.shtml
SKETCHY MATH, just to eyeball it:
If you scroll down and look at the Player Advanced Fielding -SS, it seems like the Plate Appearances for the opposing team (per full time, healthy SS) is somewhere in the 4.5k to 6k zone. The number of balls a shortstop actually fields (PA/Fld) seems to be in the 10%-11% range for the SS who have the most opportunities - Aybar, Andrus, Cabrera, and they also range in the 87% to 91% in actually creating an out on a fielded ball.
I like looking at these numbers because it makes sense to me that the number of balls hit through a SS "zone" or "window" or whatever will average out. Guys with great positioning or physical athleticism will be able to get to a greater number of balls in the window. So if we know the number of times a SS actually fields a ball v. the number of PAs they're there for, we can get a "range" number as a percentage of total PAs. I'm sure there are better numbers to use, but this works for my thumbnail analysis. (UZR seems so overworked sometimes - over 150 or so games, some guys are just, for whatever combo of reasons, going to catch the ball more - the question is, how often do they catch the ball?)
So too, the conversion number (F2O%) measures strong arm, good instincts, whatever combination it takes to make a fielded ball into an out. Again, not perfect numbers for projection, as you could have a guy with high talent and jitters match up with guy who has low physical talent but perfectly uses that talent. But still, it's a number.
Aybar, Andrus and Peralta all had about the same # of PAs, but Aybar and Andrus actually both fielded 529 balls, and Peralta only got to 468. Running that through the percentage resulting in outs (F2O%) gets us, 460, 469, 425 outs per season. Which is an interesting spread to me. 40ish outs seem significant to me.
If we assume the number of PAs when a healthy SS plays is say, 5K, and for whatever reason, an "average" healthy young SS will get to 500 of those at an averageish 10% clip, and convert 88% if them to outs, you have a 440ish out baseline, for a healthy SS with good range.
So a "perfect storm of crap" season gets you fewer chances/poor range/crappy throws result of, say, 4.7K, 8%, 85% (4700/376/319) or 319 outs. Or 120 outs below my "baseline".
A "perfect" season of high chances, great range/positioning, great conversion of, say, 5.6K, 12%, 92% (5600/672/618) or 618 outs, 178 outs above my "baseline".
(Or an average chance season for a physically gifted SS of 5K, 12%, 92% (5000/600/552) or 552 outs, 110 outs above the baseline)
Yes, I know these are crap numbers: I'm just trying to eyeball it.
I think it makes sense though, if we assume the number of balls hit through a SS "zone" or "window" is more or less consistent over a season, one good way to measure, roughly, range, is the number of balls a SS actually fields. It seems that number is the most important - which is basically "range," but we can say it also takes in initial positioning, etc. - it's "getting to the ball-ness." So with these thumbnails, over the course of a season, if you've got a guy who makes not a highlight play, but a "yeah, really good range on that guy" play once a game, you're at 162. That seems reasonable to me if we're truly talking about an elite defensive talent who plays all year. Or downgrade it to 100 fielded balls - whatever.
Conversion to outs seems to vary somewhat (and I'm just going with the F2O% numbers) but it looks like 85-91 seems like the reasonable range in 2011. If you factor in range v conversion, high conversion on the low end of range (91% on 400 fields = 364 outs) is not as good as low conversion on the higher end of range (85% on 529 fields = 449 outs).
So the actual out differential between a "solid" and an "amazing" ss might be what over the course of a year? 75 to 150 outs?
If that's even roughly correct (and I think it is, largely because of the number of balls good range/positioning lets you field) it's not only blanketing the opposing offense you have to figure, but the synergistic effect of letting your starters go deeper. If the starters go deeper, you bridge to your elite relievers more easily (in tight games), so a large percentage of your additional theoretical 100 outs could be expressed in not using crappy middle relief guys.
As a final caveat, I'm CERTAIN there's a lot of noise in those numbers. If anyone does spreadsheets, etc, it would be great to see a better analysis along these lines. What seems to be key though is the number of balls a SS actually gets to - huge difference on the number of outs made.
(edit - BTW, if we look at the AL league average numbers, the average PA is 6173, the Fld is 579 (which equals a .09% "range"), and the F2O% is 88%, for 509 outs. But that's really a league average SS that plays every inning of every game.)
Edited by Rovin Romine, 23 March 2012 - 12:37 PM.