Test Driving Statcast’s Newest Bat Tracking Metrics

On Monday night, just after midnight, Major League Baseball released a bevy of new bat tracking data. It was accompanied by the now customary combination of an explainer from Mike Petriello and a breakdown of the most extreme players from David Adler. Like many people, I’m still trying to wrap my arms around how these data work and what we might be able to learn from them. Bat tracking metrics are complicated because swings are complicated. The various numbers are interconnected, dependent on location, pitch type, and the batter’s tendencies and intent. There’s no one perfect way to swing, and it’s easier to draw inferences about individual players than overarching conclusions. My first takeaway was that something weird is going on with Leody Taveras. I’ll write about that tomorrow, but for now I’d like to take the new metrics for a test drive. We’ll look at two specific pitch archetypes to get a sense of what these numbers do and how they look in action.
Let’s start as simple as we can. I pulled the league-average numbers for swings against four-seam fastballs right down the middle in zone 5, but I split them up. The top row shows the numbers only for competitive swings on hard-hit balls. The bottom row shows the numbers only for competitive swings that resulted in whiffs. Let’s see how these two swings might differ.
| Result | Bat Speed | Swing Length | Attack Angle | Attack Direction | Swing Path Tilt | Intercept X | Intercept Y |
|---|---|---|---|---|---|---|---|
| Hard-Hit | 73.6 mph | 7.2 ft | 8° | 2° OPP | 32° | 36.5 in | 28.5 in |
| Whiff | 73.5 mph | 6.9 ft | 3° | 12° OPP | 35° | 37.0 in | 21.2 in |
Plenty of differences jump out at you here. When a hitter misses a four-seamer right down the middle, it’s usually because they’re behind on it or under it. All of the new metrics are telling us that in their own way. I’ll capitalize all the metrics in this article, just so we get comfortable with their names and definitions. Read the rest of this entry »






