No, it's not a version of UZR or plus/minus, but it's something. It's a version of Sean "CHONE" Smith's TotalZone, so I believe that, like TotalZone for the majors, it uses RetroSheet )or RetroSheet-style) data to reconstruct, as best as possible (with heavy regression, etc.) hit location. Very interesting stuff. Smith has an interesting piece on historical fielding numbers (reconstructed from Retrosheet) in this year's THT annual.
The usual caveats about defensive metrics (particularly ones that don't have hit location available) and player development apply, of course. Keep in mind the small sample sizes, that players are usually away from their defensive peak (and in many cases, are learning new positions), and so on. So this in no way should be taken to "overrule" scouting reports.
Still, this is a cool thing, and TotalZone is generally considered to be right there with the best of its kind (with Dan Fox's no-longer available Simple Fielding Runs, Pizza Cutter's OPA!, etc.).
h/t to R. J. Anderson and Beyond the Box Score
Also cool that they have home/road splits, which I don't see elsewhere.
Interesting numbers:
Mike Aviles (linked page above):
At SS:
2005 -4
2006 0
2007 +2
2008 +3
at 2B:
2005 -4
2006 +8
2007 +4
2008 +6
Billy Butler at 1b:
2007 +1
2008 -2
at LF
2005 -18 (total)
2006 -9
at RF
2006 -35
MITCH at CF:
2005 -3
2006 -14
2007 +10
2008 +13
Joe Dickerson
2005 -23 at CF, 0 at RF
2006 -2 at CF
2007 -1 at CF, -8 at LF
2008 +1 at RF
D-Rob
2006 -3 at CF, +1 at RF
2007 +1 at LF, 0 at RF, -14 at CF
2008 +5 at CF
Jeff Bianchi:
2005 +10 at SS
2006 +1 at SS
2007 -1 at 2B, +5 at SS
2008 +9 at 2B< -2 at SS
Huber (LF only)
2006 -11
2007 +7
2008 +1
Kila:
2005 +2
2006 +4
2007 +5
2008 -3
