New technology analyzes defense with distance covered, running speed, route efficiency
By Mike Petriello
It's the classic baseball barroom argument: Take two similar spectacular defensive plays and argue about which one was more impressive. It's the perfect baseball discussion simply because one side could never conclusively prove the other wrong. As long as the out was made, the rest was just speculation and perspective. You could take two or 10 or 20 similar plays, and they'd all be essentially tied for first place.
For decades, particularly before the advent of nationally televised games, there was no way to do better.
Fortunately for us, we live comfortably in the future, and we can do better -- much better. Over the past few days, Pittsburgh's Andrew McCutchen and Minnesota's Jordan Schafer have each made an outstanding grab in center field, both running in to make a diving catch just before the ball touched the tip of the grass.
Objectively, they looked close to identical. Even applying some of our Statcast™ technology, there was a lot about them that was similar -- McCutchen ran 58.6 feet to get to Kolten Wong's drive, while Schafer went 59.4 feet to rob Billy Burns. Their acceleration was identical to the first decimal point (3.1 seconds to reach top speed for Cutch, 3.2 for Schafer). It's about as close as two plays can get.
So which was better? The two pitchers who saw their center fielder save them from allowing a potential extra-base hit might not care to worry about it, since the out was recorded in each case. But we're trying to get deeper than that, and we can dig into the data to find one area where the two catches differed: route efficiency.
It may be a new term, but like most advanced baseball terminology, it's trying to answer a pretty simple question: How far did the fielder go between his starting point and where he made the catch? Which is another way of saying, "It's a whole lot easier to get to the ball quickly when you're not adding extra distance to your travels." In the same way walking three blocks out of your way when you're just going to the corner store adds time, a less effective route to the ball adds time -- and difficulty.
Now we've found our difference. McCutchen's route efficiency was 99.2 percent, which means that only 0.8 percent of his travel was unnecessary, or the equivalent of a few inches. It's clear to see that on the video -- as soon as the ball is hit, he's immediately charging in towards his target. Schafer's efficiency was 92.5 percent, which, multiplied by the distance he had to go, meant he actually went approximately five feet out of his way to catch the ball.
You can see that on the highlight, as Schafer takes more of a curved path than McCutchen did. Though they ran nearly the same distance, only McCutchen needed to, and you can see that in the fact that his first step was 10 degrees more direct to the ball than Schafer's. (It also helped that McCutchen ran faster, reaching a top speed of 19.2 mph, as opposed to Schafer's 17.9 mph.)
It may seem that there's not a whole lot of difference between 92.5 percent and 99.2 percent, and that's true, but remember that we're comparing two outstanding defensive plays. You don't get to have a 50 percent defensive efficiency and still make a diving catch unless you've really botched something that should have been routine in the first place, and that's really what this is all about in the first place.
For too long, "diving catch" was the definition of "good defensive play." We always knew better. Now, thanks to Statcast™, we can know better.
Mike Petriello is an analyst for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.