Pierce Johnson Is Baseball’s Curveball King

Pierce Johnson seriously throws so many curveballs.

In the early days of the professional game, curveballs were illegal to throw. Had Pierce Johnson pitched in those days, he’d be ejected on nearly two-thirds of his pitches (throwing overhand also wouldn’t endear him to 19th-century umpires). It’s incredible that a pitcher would throw a curve that often and succeed.

How unbelievable is Johnson’s 67.5% curveball rate?

Only three players in the pitch-tracking era of baseball have eclipsed 60%. Only six have even thrown it more than even half the time (min. 50 IP).

Highest Curveball Percentages

Scott Sauerbeck’s 2002 stands alone for pitchers throwing ol’ Charlie, but Pierce Johnson was hot on his tail in 2021 and came closer to eclipsing that mark than any other pitcher in history.

The odd thing about the pitch is that on the surface it doesn’t jump off the Savant page with its movement or anything. It’s well-above-average in terms of its horizontal break (57% more than league average), but its vertical drop is actually 6% below average. Yet, it’s still an extremely effective pitch, as it recorded a -14 run value last season, and despite throwing the same pitch over and over, Johnson still posted a 3.22 ERA (3.31) FIP and a 31.6% strikeout rate.

How was a curveball with better-than-average-but-not-unbelievable movement thrown more than two-thirds of the time so effective for Johnson?

The answer is in spin mirroring. Essentially, the more “opposite” the spin on a baseball is from two different pitches in a pitcher’s arsenal, the more difficult it will be for hitters to distinguish which pitch is coming based on how it looks out of the pitcher’s hand. Johnson’s curveball spins in almost the exact opposite direction from his only other pitch, a four-seamer:

To hitters, the curveball and four-seamer look almost identical and that bears out in how they perform against the pitch. Johnson’s curve recorded a 34.2% CSW last season, but an incredible 94% of those were “whiffs.” Johnson doesn’t get hardly any called strikes on the curveball, leaving batters utterly flummoxed and flailing as they have no idea what’s coming.

Again, this is a pitch Johnson throws two-thirds of the time and batters seem to be confused when they see it!

Further evidence in hitter confusion can be found with how hitters fare against Johnson’s two offerings overall. Almost all of Johnson’s “expected” stats (xBA, xSLG, xwOBA) are in the top quartile for pitchers in the league. However, the one outlier in his batted ball data comes in the form of his below-average ability to limit hard contact in the average exit velocity he allows on pitches. When hitters guess right and do make contact, they get a hold of it. Luckily for Johnson, that doesn’t happen too often.

A journeyman reliever (Johnson has played for three teams since his debut year in 2017 at age 26) having this success is fun in its own right, but to do so while coming close to throwing an elite pitch over and over again, more than almost any pitcher in history is even better.

The past two seasons Johnson has eclipsed the 50% mark in curveballs, after throwing the pitch only 28% of the time in 2018 (he pitched in Japan in 2019). Figuring out that he can throw it constantly for (swinging) strikes has unlocked a new level for him since then. He could be in the mix for the closer’s role for the Padres this season. It’s one thing to throw a pitch a ton, it’s entirely another to be so successful with it.

Pierce Johnson has taken the “why don’t they make the whole airplane out of the black box?” joke and turned it into a pitching philosophy.

Since his curveball seems to work primarily because it’s paired with an excellent four-seamer (top 20th percentile in baseball), it’s unlikely we’ll ever see an entire season of curveballs. But Johnson may get closer to that than any other pitcher in history, and it’ll push the boundaries of how good a single pitch can be.


Photo by Larry Placido/Icon Sportswire | Adapted by Michael Packard (@artbyMikeP on Twitter & IG)


Sean Roberts

Sean Roberts is a baseball columnist for Pitcher List. His work has been featured on Baseball Prospectus, the Hardball Times, and October. He's still getting used to the DH in the national league. @seanroberts.bsky.social

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