The Filthiest Pitches in Baseball

As a follow up to my piece on Whiff Rate as a leading explanatory factor for strikeouts, I thought it would be interesting to look at which pitches caused the highest rates of Whiffs in baseball.

Since Ben at Baseball prospectus had already identified the surprising leaders and Jeff at Fangraphs identified the top pitch overall, my idea kind of evolved into highlighting the filthiest pitches in baseball in more broad terms rather than just with Whiff Rate.

As such, today I’ll take a look at each pitch type as classified by Brooks Baseball PitchFX, highlighting the pitchers who had the best fastball, slider and more, in terms of Pitch FX Horizontal Movement, Vertical Movement and Whiff Rate, as well as Fangraph’s Pitch Values.

Minimums & Caveat

As Bill pointed out, we have to be careful with the pitch value measures due to confounding factors. Tango cautioned as much, too, reminding us not to evaluate an interdependent dynamic like pitch mix as independent items That is, a changeup may look spectacular because of a strong fastball, or to steal an example, a Dickey fastball may perform better than expected since hitters are looking for the knuckler. So take these designations of "best pitch" or "filthiest pitch" with a grain of salt, and understand they're just for fun.

All charts use a minimum of 200 pitches thrown and 40 innings pitched for relievers and 400 pitches thrown and 80 innings pitched for starters as the cutoff. The movement values refer to the change in location due to spin on the ball compared to a spin-free ball. Whiff/Swing is the percentage of swings that results in a miss. Pitch values are in terms of runs above average per 100 pitches.

Fourseam Fastball

"Old reliable" is a pitch that just about every pitcher fires out there are least some of the time. In fact, 279 starting pitchers threw at least one this year while an additional 468 relievers tossed at least one. Kelvin Herrera topped the charts with an average fastball velocity of 99.41, but there’s more to a heater than just the gas.

No surprise here as Craig Kimbrel dominates in terms of the value produced from the heater – it’s why we’re now referring to striking out the side as The Kimbrel. On the starter side, there is a solid mix of candidates, although in terms of total (non-per-100-pitches) value Kershaw is the "winner."

Slider

The "most dangerous pitch in the game" can refer to the tax in puts on a pitcher’s elbow as well as the damage it can do to a hitter’s pride.

Yu Darvish appears to be the best starter in terms of getting the most out of his slider thanks to some sick movement away from right-handed batters. On the reliever side, it appears it’s not just batted ball luck that has helped Mitchell Boggs to a career year, though it’s Joel Hanrahan who has the most unhittable slider in terms of getting a piece of it.

Cutter

The Orioles may not believe in the cutter, but there are a lot of pitchers who employ it religiously, including two of the best of our generation in Roy Halladay and Mariano Rivera.

It’s possible Darvish deserves the crown over Luke Hochevar (who I was surprised to see on any kind of leaderboard), as depending on the pitch classifications Hochevar may or may not qualify. On the reliever side, Jansen’s cutter sure doesn’t seem to move like a cutter, more like a curveball, with so much vertical movement.

Curveball

The hook is a useful out pitch for many hurlers, and it probably looks better than any other pitch on a replay, displaying the ability to make hitters look foolish with heavy movement.

Clayton Kershaw missed the cut off by a half dozen curveballs, so you can consider him the best fastball-curveball mixer in the league without much argument. Fiers is interesting since his curve has so much drop to it but it rated as completely neutral in terms of value, meaning he could be tipping it or failing to locate it. Lincoln’s curve passes the stats test but since he only as a fastball and the hammer, he still struggled. With Lyon in the mix and former Jay prospect Collins on the leaders, it seems Toronto has a thing for the curveball.

Changeup

The change can complement a fastball by changing speeds and throwing hitters off balance, and it’s unique in that it tends to have reverse platoon splits.

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