I know that Ryan Zimmerman had 17 errors, while Kevin Kouzmanoff had just 3. Yes, 14 errors is a big difference. But there’s more to defensive excellence than just errors and fielding percentage. Basing a fielder’s overall performance on only those two measures is like judging a starting pitcher’s performance on just his W/L record, without looking at his ERA, WHIP, run support, etc.
Below are the basic statistics that are used to compare defensive performance of players — Zimmerman’s and Kouzmanoff’s stats are shown.
Player TEAM POS G GS INN TC PO A E DP RF FPCT
Zimmerman WSH 3B 154 153 1337.2 459 117 325 17 28 2.97 .963
Kouzmanoff SD 3B 139 134 1186.2 311 94 214 3 24 2.34 .990
As you can clearly see, Zimmerman had more total chances, more put-outs, more assists, more double plays, and a better range factor. Kozmanoff has the edge in errors and fielding percentage. Note: Zimmerman lead the majors with his 459 total chances and 325 assists.
Another stat that has been mentioned when comparing Zimmerman and Kouzmanoff is UZR — Ultimate Zone Rating. Zimmerman lead NL third baseman with his 18.1 UZR. According to THIS ARTICLE, Zimmerman also lead NL third baseman in range factor and range factor per game.
I am not a stats geek, in any way, shape or form. I attempted to learn more about UZR by going to FanGraphs.com and reading their UZR Primer (parts 1 and 2), and I came away from it all with a headache. You know how cartoon characters have stars and birds circling their heads when they get hurt? That’s exactly how I felt after trying to figure out UZR.