Evaluating defense in baseball continues to be a work in progress. We’re way better off than we were even a few short years ago, but it remains a tricky and often subjective undertaking, with most people not being able to say much more about the topic apart from “that guy plays good defense” and “that guy is a liability.”
Against that backdrop, Baseball Crank spent an enormous — and I mean a really, really enormous — amount of time analyzing team defense between 1871 and the present, focusing primarily on Defensive Efficiency Rating. It’s in two parts: here’s part 1 and here’s part 2. There are stats, but it’s not too hard core, and Crank does a good job of explaining what he’s talking about as he goes along.
Great stuff if it’s a topic that jazzes you.