Well, again, they're the 26th-best defensive team in MLB. Not making errors doesn't necessarily mean good defense. Good defensive teams usually are winning teams. The Cubs of last year were a (glaring) exception. Where are you getting this from? http://www.baseballprospectus.com/statistics/sortable/index.php?cid=204024 I am a little less inclined to look at those type of statistics when it comes to defensive ability. I think defense, moreso than hitting or pitching, can be judged better with your eyes. For instance, I don't think I would consider this Cubs team to have a great defense, but according to those numbers they are ranked 3rd. Individually, yes, but team defense is different than the sum of the individual parts. While defensive efficiency isn't perfect(the Cubs can likely attribute that rating to their K happy pitching staff), it provides a fairly accurate picture of how well the entirety of the defense has been for a particular team. I'm not sure how K's would figure in. Defensive efficiency measures the percentage of balls in play that are turned into outs. K's don't factor. But I agree with your point: whatever you might believe about measurements of an individual's defense, team defense IS pretty easy to quantify with statistics.