Why the Diamondbacks Are in First Place

If you’re like me, you’ve been assuming the Dodgers would end up in first in the NL West for a while. Indeed, our playoff odds are still big fans, because it’s hard to overlook the track records of the various players around the Dodgers’ roster. If I had to make a prediction right now, I’d still settle on the Dodgers to be there at the end. Maybe that makes me smart. Maybe that makes me stubborn. Could be a little of both. I don’t like to be put on the spot.

But for however much talent the Dodgers possess, on August 16 we’re looking at the first-place Diamondbacks. The club’s been playing .500 baseball for a month and a half, yet still, they’re looming above the Dodgers and Rockies. When it comes to explaining why the Diamondbacks are where they are, credit has to go to good hitters like Paul Goldschmidt, David Peralta, and apparently Daniel Descalso. Credit also has to go to good pitchers like Patrick Corbin and Zack Greinke. And then there’s the helpful matter of so-called “cluster luck” — the Dodgers have a better run differential than the Diamondbacks do. No team reaches first place because of one reason alone.

Here, however, I’d like to shine some light on the Diamondbacks’ greatest strength. To this point I’d say it’s gone underappreciated, but I’ll show you the evidence in seven plots. The Diamondbacks have had an incredible defense.

I’m going to split this up and proceed area by area. And to get right to the point, let’s take a look at league-wide catcher defense. This information comes from Baseball Prospectus, and these numbers try to include everything, from pitch-framing to pitch-blocking:

The one thing we don’t really understand is game-calling. That part might be hopelessly complicated. Based on what we can analyze, though, the Diamondbacks have had the game’s best defensive catchers, largely because they’ve had the game’s best receivers. In case you want some supporting evidence, you can find on Baseball Savant that Diamondbacks pitchers have gotten the highest called strike rate on pitches taken around the edges. That’s the framing impact. And Defensive Runs Saved also has a catcher-defense column. The Diamondbacks rank first there, too, at +18 runs. Everyone, then, is in agreement, and most of this is because of Jeff Mathis and John Ryan Murphy. I should tell you we’re only just getting started.

That’s catchers. How about pitchers? We don’t talk that much about pitcher defense, because pitchers usually don’t get that many defensive opportunities, but there’s a DRS column that we might as well consult. Not only do pitchers get to try to make some plays on batted balls; they’re also mostly in control of the running game. Here’s the landscape of team pitcher defense, according to DRS:

First-place Diamondbacks. Sure, they’re at just +10 runs, but then, ten runs is basically a win. They’ve made good plays on batted balls, and they’ve picked off a handful of runners, while preventing others from stealing many bases. Not much more that pitchers can do in this department. So with catchers and pitchers down, why not turn our attention to the rest of the infield?

For the next two plots, I decided to take the average of each team’s DRS and UZR. I don’t prefer one to the other, so I settle by splitting the middle. The infield picture:

Seventh-place Diamondbacks. Seventh isn’t first, but it’s still pretty good. Besides, I’ll have more to say about this later. Here’s the outfield picture:

Third-place Diamondbacks. First behind the plate, first on the mound, seventh around the infield dirt, third on the outfield grass. Already, that’s painting a rosy picture. But of course, as I feel like I constantly remind you, it’s the Statcast era! We might be able to do better than DRS and UZR! Those measures don’t do very well when it comes to handling defensive shifts, or non-traditional alignments. As you know, non-traditional alignments have become the modern-day traditional alignments. So let’s play with something. You know what wOBA is. By now, I imagine you also know what expected wOBA is. It stands to reason that, if you look at the difference between the two, that should have some good relationship to defensive performance. Ballpark environment is also a factor — as always, Coors Field is weird — but just for the hell of it, here’s the landscape of 2018 differences:

Right away, you’ll notice almost every team is below zero. That’s because xwOBA is calculated over multiple years, and this year the ball hasn’t been as lively as it was in the recent past. What’s most important is where each team is, relative to one another. Here we see the Diamondbacks in second, behind only the A’s. The A’s also have a good defense! The A’s are the team with Matt Chapman.

That’s the overall xwOBA picture. Here’s how it looks when you narrow to only grounders and pop-ups, which I’m using as a proxy for infield defense:

The Diamondbacks are in first, ahead of the Chapman infield. Remember, according to combined DRS and UZR, the Diamondbacks infield ranks seventh. I don’t know if I can say confidently that this is a better metric, but it’s probably at least as good. The infield defense has evidently been strong. And now, here’s the xwOBA picture on flies and liners, which I’m using to measure outfields:

Almost everyone’s below zero because, again, the ball hasn’t been flying like it did. Based on xwOBA alone, there should be a higher league-wide homer total. That’s not what matters, for this post. The Diamondbacks here show up in second place. This doesn’t account for, say, outfielder arms, and that’s not where the Diamondbacks shine, but covering ground and catching balls is the component of greater significance. The other numbers suggest the team’s outfield defense has been good. This backs that suggestion up. Based on the batted balls the Diamondbacks have allowed, you’d expect far more hits than they’ve actually given up. That’s a credit to the players in the field.

This isn’t the most thorough analysis that could ever be conducted. I haven’t bothered to talk to anyone, and I haven’t bothered to look up whether the Diamondbacks have been playing around with different shifting strategies. I don’t know what, exactly, they might be doing differently in the field. It’s probably at least as much about the personnel. Someone else can attempt the deep dive — interviewing the players, talking to the front office, embedding videos of plays made that wouldn’t have been made in seasons past.

All I really want to do here is make a basic point. It’s moderately surprising the Diamondbacks are still in first place. Many different factors have combined to get them there, but on the defensive side of the equation, no team in baseball has been getting better defense from its catchers. No team in baseball has been getting better defense from its pitchers. Few teams, if any, in baseball have been getting better defense from their infielders, and few teams in baseball have been getting better defense from their outfielders. All things considered, the 2018 Diamondbacks have had the best defense in either league. Defense can never win a team a game on its own, but it can make little differences pitch after pitch, and play after play. Over the course of a full baseball season, those little differences have an awful lot of time to accumulate.