A physics lesson from a Joc

Game 2 of the World Series was eventful last night.

The Chicago Cubs evened the series on the back of Jake Arrieta’s pitching, with him making the longest no-hit bid in the World Series since 1969. Everybody’s favorite story line, Kyle Schwarber pitched in a couple RBI groundball singles, and Ben Zobrist knocked a triple to extend the Cubs lead.

But let’s step back to something more fun.

There was a play in the NLCS where Joc Pederson got fooled and turned around by the movement due to rotation of a fly ball. That prompted Dr. Alan Nathan to break down the physics, using Statcast data given to him by an “anonymous benefactor.”

Very cool stuff. Here’s the play in question:

There is a way in which this fly ball was somewhat unusual, in that it was hit directly at Joc Pederson. That means that from Pederson’s perspective, all movement of the ball relative to the line between him and home plate was due to spin, as opposed to normally, where the outfielder’s path is only due in a very small part to the spin deflection. That means that in terms of what Pederson has to do in the field, it’s much more weighted toward understanding the spin deflection.

Think of it this way. If the ball was hit to Pederson’s right, he starts heading right, and then adjusts his route slightly based on how the ball is spinning. But in this case the adjustment based on how the ball spun was on whether to turn his whole body one way or the other.

I think this is something to consider for pitchers, too, as they think about location and movement: how do you locate your pitch so that it’s movement matters most? Are there some locations for some pitches that make the batter’s decision easier and others that make it harder?

Read the piece here.