January 19, 2021

Hyun Jin Ryu’s Multiple Fastballs (FanGraphs)

Watch any amount of baseball these days, and you’ll see a familiar pattern: a catcher giving a pitcher a high target for his fastball. This is hardly a secret; it’s so obvious, in fact, that I don’t really know how to make a good introduction out of it. Did you know that pitchers throw four-seam fastballs high in the zone? You did! I don’t need to tell you that. But this article is about four-seam fastballs, so the paragraph feels necessary.

Anyway: Four-seamers work better when they’re thrown up in the zone. That’s not some silly contextual thing, or even really up for debate. It’s just how the pitch works. The backspin on the pitch means that hitters generally make contact under the center of the ball. Given that the normal launch angle for a ball up in the zone is already high, hitting under a high pitch means pop-ups and lazy fly balls. It also means whiffs.

Don’t believe me? I mean, first of all, just watch some baseball. The pitch that dots the top of the strike zone makes hitters look foolish with great frequency. You can also take a look at this table, which divides the strike zone into vertical thirds and looks at only four-seam fastballs:

Read “Hyun Jin Ryu’s Multiple Fastballs” at FanGraphs