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I'm getting increasingly interested in DER, which I don't understand at a very high level even though it's apparently so obvious they've named it "DER!!!!!" DER stands for "Defensive Efficiency Rating" and the A's seem to rate really high in it. The little I know about DER is that it rates how well a team converts "balls in play" into actual outs. And the A's seem to do that really, really well.
If I'm reading this chart right, with a .707 DER (meaning the 2012 A's convert 70.7% of balls in play into outs), the A's currently rank #2 in MLB, behind only Seattle. Park effects are certainly relevant here, but are only a piece of the overall puzzle.
Perhaps a "relatively undervalued" metric like DER could help explain the gap between the way the A's look on paper and the way they look in the standings. Could the A's DER account, as much or more than the "home park" factor, for why their pitching staff looks "good" but gets "great" results? And how does a team that has put Chris Carter at 1B, Jemile Weeks at 2B, and Yoenis Cespedes in LF, rate high in a defensive metric?
Then I think about the game where Balfour gave up seemingly a game-tying line drive single up the middle -- only it was speared by Weeks who was shifted strongly up the middle. We saw it again on Friday night, when Matt Joyce's sharp grounder by the mound was fielded easily by Stephen Drew thanks to the shift.
Are the A's leading the league in "defensive positioning"? In "smart shifting"? Or is it that they lead the league in inducing "easier to field" grounders and fly balls? Or are Brandon Inge, Coco Crisp, and Josh Reddick so good at defense that they more than cover for the weaker defenders? Or does Oakland's home park give them just enough of an edge to rank them high instead of middle?
If someone who truly understands DER has insights to add on why the A's are so strong in this area, I'd be really interested in dissecting what the A's might be doing behind the scenes -- be it with spray charts, "avant-garde shifting," or "pitching for weak contact," that allows the A's to excel in this important area. Because they seem to convert an awful lot of balls in play into outs for a team with several players who don't excel at defense.
