The D-Backs Could Have a New Pitching Approach

The Diamondbacks are one of two potential NL West sleepers. One thing they have going for them is that, this year, they should get something like a full season from A.J. Pollock. But then, beyond him, there’s the potentially electric starting rotation. Although there are more questions every day about the well-being of Zack Greinke, he’s followed by names like Shelby Miller, Taijuan Walker, Patrick Corbin, and Robbie Ray. Inconsistent, the lot of them. But they’ve all been well-regarded before, and you never know when a young pitcher could have everything click.

One mission for the team, then, is to try to squeeze everything it can from the pitchers it has. You can try to get the pitchers in better shape, and you can try to work out kinks in their mechanics. Every pitcher on the planet wants greater release-point consistency. But how about just changing how pitchers pitch? It’s early, but there’s a sign something could be changing down in the desert.

In recent years, Diamondbacks pitchers have worked down with gusto. And it makes a certain amount of sense — their home park is a hitter-friendly environment, and you’d be inclined to think pitching low would generate grounders. Grounders aren’t homers! You know this line of thinking.

I did my research using Baseball Savant, and I focused on its zone breakdowns. Baseball Savant bins all pitches into one of 13 zones, and I was interested in the rate of pitches thrown in the five lowest. Last season, the Diamondbacks threw more than 59% of their pitches in those five low zones, which was the highest team rate in baseball. The year before, they were at 58%. The year before that, they were at 57%. High rates, across the board.

Here now is a plot, showing the Diamondbacks, and also the league average. I’ve included a couple points for 2017. As you’d be right to point out, no, that’s impossible! There has been no 2017! But there has been spring training, with its limited data set. The Diamondbacks’ data set is one of the least limited. Again, spring training is never conclusive, but it can be suggestive.

The Diamondbacks have thrown low at a greater rate than average every year since 2009. Over the past three years in particular, they’ve exceeded the average by six, five, and six percentage points. In the spring-training data that’s been recorded, they’re lower than the average by two percentage points. No other team has seen so great a shift, which is what makes this notable.

Last year, the Diamondbacks had the highest rate, out of 30 teams. This spring, the Diamondbacks have the fourth-lowest rate, out of 16 teams for which any data exists. (There is no pitch information that comes out of Florida.) It’s important to consider the greater context, instead of numbers in isolation, because the baseline can and does move. Like, for example, you see that the league overall has thrown low less often this spring, if the data is to be believed. Maybe the instruments aren’t all properly calibrated. Or maybe teams really *are* throwing low less often, perhaps because a lot of baseball people believe the strike zone has shrunk. Within the context, the Diamondbacks have shifted. They’ve shifted by enough to warrant attention.

Here are some side-by-side heat maps, also from Baseball Savant, if heat maps are your thing:

There seems to be a clear reduction in pitches down. It just shows the earlier information in a different way. It’s all, of course, coming from the same source.

You’d be right to point out that spring-training data can be complicated by appearances by non-major-leaguers. There are plenty of Diamondbacks who have pitched this spring who won’t sniff the bigs any time soon. I don’t think this is a big issue, though. The two leaders in recorded pitches this spring are Ray and Miller. They’re followed by Greinke, Keyvius Sampson, Corbin, Archie Bradley, and Jorge de la Rosa. This doesn’t seem like a set that’s skewed. It’s more likely to reflect something intentional.

Which doesn’t mean it does reflect something intentional. But if there’s something specific being implemented, well, it’s not as if the Diamondbacks aren’t going through a whole bunch of other changes. Last October, they picked up a new general manager. Last November, they picked up a new regular manager. Welington Castillo is gone, and Chris Iannetta and Jeff Mathis are new. The group of catchers has been updated, and when you have a new organizational hierarchy, it makes sense the new guys could bring new organizational philosophies. The previous leadership seems to have been big on the idea of pounding the lower part of the zone. There’s evidence to suggest the team now will want to more frequently explore the upper bits. It could help to unlock some of the potential still hidden away in the assortment of promising arms.

It could go nowhere. It could always go nowhere. And it’s entirely possible I’m seeing something in the data that isn’t actually there in real life. That’s the danger of spring-training data interpretation, and so, as usual, I await further evidence. What’s clear is the Diamondbacks have a lot of pitching potential that remains untapped. They’re also coming off a massive organizational shake-up that presumably has introduced some new ways of thinking. Improvement isn’t always about refining one’s pitches. Sometimes it can be about using the same pitches in different ways.