The Royals find themselves in an interesting situation. They're in the World Series! Wow! And within that, with the series shifting now to San Francisco, the Royals are in an interesting sub-situation. Alex Gordon ought to start in the outfield, obviously. Lorenzo Cain ought to start in the outfield, obviously, as well. But then you've got Norichika Aoki and Jarrod Dyson. Aoki has been the starter in right field for a while, but now with the rules changing for three games, it's time for Ned Yost to also make a change and keep Aoki on the bench at the beginning. Kansas City should go with the ultimate outfield.
This isn't just a hypothetical suggestion, by the way. The matter is on Yost's mind. Sometime Friday, he'll make his call, and while it's generally safest to bet on continuity, Yost's been nothing if not unpredictable these last few weeks.
The ultimate outfield looks like this:
LF: Gordon
CF: Dyson
RF: Cain
Cain, defensively, is outstandingly good. So it tells you something that Yost likes to have Dyson in center field, with Cain shifting to right. Actually, it tells you a couple of things: Dyson, also, is outstandingly good, and Cain might well be more comfortable in a corner. Anyhow, the difference between the ultimate outfield and the ordinary outfield is that Dyson subs in for Aoki, and swaps places with Cain. The ultimate outfield is weaker at the plate, but is just stupid good not at the plate.
Dyson bats left-handed. Aoki also bats left-handed. There's a strong argument to be made that the Royals should use the ultimate outfield against all right-handed pitchers. But that obviously wasn't going to happen with the Royals playing by American League rules. Now, the National League rules change things up somewhat. They should provide enough incentive to pencil Dyson into the starting lineup.
The next section is going to be a pretty straightforward Dyson vs. Aoki comparison. This is old-school, 2007 analysis, but it still works just fine today. The other players aren't really affected, save for Cain, who's got two potential positions to play. So how can you make a decision between Dyson and Aoki? Well, you make a decision about their value. And their value comes from hitting, running, and defense. There's one more thing, but that'll come at the end.
I want to go light on the published math. However, the math has all been performed, and I've got the evidence handy on this spreadsheet right here. The most complicated part is figuring out how Dyson and Aoki should be expected to hit, against right-handed pitchers. I don't care that Aoki is hitless in the World Series. He hit .304 over the two previous rounds. And far more importantly, we have far more information than that. We have Aoki and Dyson's full careers! And we have statistical projections!
Are you familiar with wOBA? It's an awesome batting stat, scaled to resemble OBP. You don't have to know the details; you just have to know that higher is better. Dyson's projected for a .291 wOBA. Aoki, .330. Aoki's clearly the better hitter. Everyone already knew that. Dyson and Aoki already knew that. But, say, look at this:
Dyson vs. RHP, career: .308 wOBA
Aoki vs. RHP, career: .323
Well that shrinks the gap. Unfortunately, it's not that simple. You can't just throw out what Dyson and Aoki have done for their careers just against lefties. Those are also meaningful plate appearances, and Aoki has hit lefties better than righties, while Dyson has sucked. Here comes the really mathy bit. We know from prior research that these platoon numbers have to be regressed pretty heavily. That is, there's a difference between what the numbers say, and what the numbers would say over an infinite sample. Here's a link to a good explanation, that also includes some example math. I'll skip the details and just show you this: I'd project Dyson for right around a .300 wOBA against right-handed pitchers. Aoki, just north of .330. That's a substantial gap, and over the equivalent of a full season, it works out to a difference of about 16 runs.
If you retain one thing, retain that. By the math, over a full year, Aoki would be about 16 runs better at the plate against righties than Dyson. Now we can move on.
Baserunning? Dyson's an awesome baserunner. That's why the Royals like to use him as a pinch-runner. Over his career, he's been 23 runs better than average. Aoki seems like more of an average sort, give or take a few runs. Clearly, Dyson has the advantage here, and let's call it five runs or so over a hypothetical season. Maybe the gap's even as big as ten, but five works well enough.
And that takes us to defense. You all know that defense is a difficult thing to measure. You also know that we do have measurements, and they're not just made up. You know that Dyson seems like a great fielder. You know that Cain seems like a great fielder. You know that Aoki is a roller-coaster, no idea if it's going to kill you somewhere along the track. Aoki's the worst of the three, probably without any argument. And the numbers build an even stronger case.
By the information we have, Dyson's been something like 20 runs better than average in center field over a full-season denominator. The exact same thing applies to Lorenzo Cain: statistically, they're two of the best center fielders on record. Cain has looked even better than that in his more limited time in right field. Meanwhile, Aoki as a right fielder has been something like five runs better than average, and he scores worse by the eye test. You can see where this is going.
Forget about the actual numbers, for a moment. Aoki seems to be about an average right fielder, maybe a little better. Dyson and Cain seem to be elite center fielders. An elite center fielder would be an elite right fielder, and that's what Cain's numbers support. So what would be the difference, over a full season, between an acceptable defensive right fielder and an outstanding defensive right fielder? To me, the gap's at least ten runs, and it might well be as many as 20. The numbers say 20, but all crazy-looking numbers have to be regressed to something a little less crazy.
Now look where we are. If you skimmed all that, that's fine. But, Aoki is the better hitter than Dyson. Something like a third of that advantage goes away when you consider baserunning. And when you consider defense, the two are at least tied up, and Dyson might definitely be out ahead, given Cain's ability to play a corner. It's a close race, and that's why you so often see Dyson subbing in for Aoki late in games. In terms of overall value, they're similar.
But now we remember that the Royals will be playing in San Francisco. By AL rules, the Royals were last in the league in pinch-hitting attempts. Dyson had potential late-inning value as a pinch-runner, mostly for Billy Butler. In the NL, Butler won't be in the starting lineup, and there will be several pinch-hitting opportunities when the pitcher's spot comes up. It makes more sense to have a decent hitter on the bench, and Butler, Josh Willingham, Terrance Gore, Erik Kratz, and Jayson Nix are all right-handed. Aoki's a lefty, and he's a lefty who's also demonstrated over his career that he's comfortable hitting against righties and lefties alike. In that way he's kind of reliever-proof.
Having Aoki available on the bench would allow Ned Yost to possibly insert him in a high-leverage situation. There's value in that, value that Dyson couldn't match as an option. Aoki could even pinch-hit for Dyson, and with Gore around, the Royals have an alternate plug-in speed source. Not having Dyson on the bench wouldn't mean they wouldn't have a pinch-runner; they'd have one, instead of two.
As players, overall, Jarrod Dyson and Norichika Aoki are similar in terms of their value. Depending on what you think of the defensive edge, Dyson could pull ahead. And with the Royals playing in an NL ballpark, there's also a bonus to be gained from having Aoki available on demand. He's a more useful bench weapon than Dyson is, and that serves as the tiebreaker, if you believe they were tied to begin with.
So far in the playoffs, we've seen a lot of the ultimate Royals outfield in seventh, eighth, and ninth innings. It's time to see it in the first.
