[mosdef]

I know what you're saying and I don't disagree with you. However, if we're going to talk about two players and guess who will be better next year, then the first place to look is last year's stats.

Without digging really deep into the numbers, I would look at WS as a single number that will give some indication of how well they played overall last year. As a first order approximation, that's an imperfect but okay guess of what they might do next year.

Now, if I really wanted to spend an hour cooking up a prediction for next year's stats, then I would try to remove non-sustainable impacts like BA in play and BA with RISP, and probably focus in on their "core" hitting stats like HR, SO, BB per PA, probably make some attempt to trend these forward based on current ages. But just looking at WS was enough, IMO, to say "these players were of roughly equivalent value last year, so it isn't clear that switching Giles for Barfield is an upgrade or not".

I understand your point, but I am not claiming that last year's WS is the ultimate stat and that it completely describes how good these guys will be next year.

Besides, Giles had a better BA with RISP so he's more clutch and therefore a better team player, too. He is also a scrappier player with more hustle.

Just kidding.