The Royals have got all of us thinking. It’s not so much about the Royals finding the only way to win, but they’ve definitely found an interesting way to win, and given their accomplishments you can’t just sweep it away as luck. The Royals have won with a bullpen-heavy model, and now it’s going to be interesting to see if other teams respond by putting more resources toward their relief. On the one hand, according to reports, there are a lot of excellent relievers on the market, as sellers try to meet perceived demand. On the other hand, I guess, every reliever addition is also a reliever subtraction, so. The point is, expect bullpens to be in focus.
And bullpens, I think, are something we struggle to measure. So much attention is paid to the difficulty of evaluating defense, but we also run into some trouble trying to value really good or really bad relievers. We’ve got reliever WAR, which takes leverage somewhat into consideration, but there’s an argument reliever WAR is missing something, something that, say, underrates how much a great reliever is really worth.
The goal here isn’t to try to answer everything. Bullpens are complicated and I can’t develop a model for everything in a day. I’ve simplified, to try to address one point. We already have reliever WAR. How have teams with an elite reliever actually done, compared to teams without one?
Read the rest of this entry »