Kodai Senga's 'Ghost' Forkball and the Filthiest Pitches of 2023 MLB Season

Zachary D. RymerApril 25, 2023

Kodai Senga's 'Ghost' Forkball and the Filthiest Pitches of 2023 MLB Season

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    Kodai Senga's signature pitch isn't an apparition of an unhittable offering.
    Kodai Senga's signature pitch isn't an apparition of an unhittable offering.Sarah Stier/Getty Images

    Being a major league pitcher isn't the sweet gig that it used to be. You can't use sticky stuff. You can't take your time. Heck, you can't even rely on over-shifted defenders and small bases to save your bacon in a pinch.

    But for all the things Major League Baseball can change, it will never be able to outlaw filthy pitches.

    So, let's look at the filthiest of them all through the first month of the 2023 season. These are pitches that not only look the part, but which also trafficking in various forms of statistical dominance. In other words, they're about as unhittable as they look.

    We have one selection for each pitch type, amounting to a total of nine. And while we will be giving honorable mentions to relief pitchers along the way, we gave the nine spotlights to starting pitchers for sample size purposes.

    As always, we owe a special thank you to Rob "Pitching Ninja" Friedman for GIFs and videos.

    Note: All stats are current through games on Sunday, April 23.

Luis Castillo's Four-Seam Fastball

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    SEATTLE, WASHINGTON - APRIL 22: Luis Castillo #58 of the Seattle Mariners throws a pitch during the first inning against the St. Louis Cardinals at T-Mobile Park on April 22, 2023 in Seattle, Washington. (Photo by Alika Jenner/Getty Images)
    Alika Jenner/Getty Images

    Key Stat: Its 43 whiffs lead all four-seam fastballs.

    Luis Castillo loves his four-seam fastball and, really, why shouldn't he?

    The Seattle Mariners ace actually threw his four-seamer less often than his changeup between 2019 and 2021, but now it's easily his primary offering and drawing whiffs on 39.1 percent of the swings against it. That's a career high.

    Rob Friedman @PitchingNinja

    Luis Castillo, 97mph ⛽️ <a href="https://t.co/uBM1kgLAVJ">pic.twitter.com/uBM1kgLAVJ</a>

    This might seem counterintuitive in context of how Castillo's average velocity is down to a career-low 95.0 mph, but that isn't the best metric for understanding his heater.

    It's better to consult vertical approach angle, which quantifies the angle at which a pitch approaches home plate. A four-seamer with a VAA close to zero degrees is considered "flat." In a good way, that is. It effectively travels the shortest distance between its release and its target, which is ideal for a pitch that's meant to beat hitters with speed.

    Per Alex Chamberlain's custom leaderboard at Tableau, the VAA on Castillo's four-seamer (minus-4.0 degrees) is closer to zero than that of the average hurler (minus-4.8 degrees). If it feels like his fastball teleports to the catcher's mitt, that's why.

    Honorable Mention: Jacob deGrom, Texas Rangers

Dustin May's Sinker

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    LOS ANGELES, CA - MARCH 31: Los Angeles Dodgers starting pitcher Dustin May (85) throws to the plate during a regular season game between the Arizona Diamondbacks and Los Angeles Dodgers on March 31, 2023, at Dodger Stadium in Los Angeles, CA. (Photo by Brandon Sloter/Icon Sportswire via Getty Images)
    Brandon Sloter/Icon Sportswire via Getty Images

    Key Stat: Its 75.0 ground-ball percentage is tied for first (min. 20 batted balls) among sinkers.

    The spotlight here should probably belong to Josh Hader's sinker. It is, after all, limiting opposing batters to an .071 average and a .101 expected average.

    But to be frank, Hader's sinker is kinda-sorta a fake one. And besides, it doesn't have the aesthetically pleasing arm-side run that the Los Angeles Dodgers' Dustin May gets on his sinker.

    Rob Friedman @PitchingNinja

    Dustin May, Filthy 98mph Two Seamer. 😷<br><br>20 inches of run <a href="https://t.co/g9jvJgrYFK">pic.twitter.com/g9jvJgrYFK</a>

    Not many pitchers pair that kind of movement with that kind of velocity when they throw their sinkers. It's really just May, Castillo (is there anything he can't do?) and Sandy Alcantara among right-handers who've thrown at least 100 sinkers.

    It's therefore surprising that May has relegated his sinker to his secondary fastball in deference to his four-seamer. He's even throwing it higher in the zone, which is another one of those seemingly counterintuitive things.

    But knowing that May also throws his four-seamer up in the zone, the idea seems to be to dare hitters to differentiate the two pitches before they behave differently upon reaching the hitting zone. As hitters are just 4-for-27 against May's sinker, the ruse is working.

Drew Rasmussen's Cutter

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    ST. PETERSBURG, FL - APRIL 9: Drew Rasmussen #57 of the Tampa Bay Rays throws against the Oakland Athletics during a baseball game at Tropicana Field on April 9, 2023 in St. Petersburg, Florida. (Photo by Mike Carlson/Getty Images)
    Mike Carlson/Getty Images

    Key Stat: Among pitches that have ended at least 20 plate appearances, it's the last left standing with a .000 average.

    It must be said that Drew Rasmussen deserves more recognition as one of MLB's best starters. In 40 appearances since he moved into the Tampa Bay Rays rotation on Aug. 12, 2021, he's pitched to a 2.50 ERA.

    As to how he's done so, it helps that pretty much everything he throws is straight-up filth. But there's little question that his best pitch is a cutter that has some unusual properties.

    Rob Friedman @PitchingNinja

    Drew Rasmussen's 7th and 8th Ks. <a href="https://t.co/cnp0g3Fl0c">pic.twitter.com/cnp0g3Fl0c</a>

    It's not the velocity that makes Rasmussen's cutter special. At 88.2 mph, it actually comes in a little slower than the MLB average of 88.8 mph.

    Rather, it's the movement. When you think of the typical cutter, you probably think of something that, Mariano Rivera-like, breaks hard and late to the pitcher's glove side. The action on Rasmussen's slider is more downward-biting, generally making it look more like a slider or even like a miniature split-fingered fastball at times.

    Whatever the case, it's flummoxing opposing batters. The 55 swings they've taken at it have yielded 19 whiffs and just two hard-hit balls.

    Honorable Mention: Luis Garcia, Houston Astros

Shohei Ohtani's Sweeper

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    ANAHEIM, CALIFORNIA - APRIL 21:  Shohei Ohtani #17 of the Los Angeles Angels at Angel Stadium of Anaheim on April 21, 2023 in Anaheim, California. (Photo by Ronald Martinez/Getty Images)
    Ronald Martinez/Getty Images

    Key Stat: At minus-9.0, it's tied with Gerrit Cole's four-seamer for best run value of any pitch.

    Remember when Shohei Ohtani's splitter was consider the most unhittable pitch in baseball? It feels like that was forever ago.

    The pitch of his that's all the rage these days is, of course, his sweeper. He loves it so much that he's throwing it more than twice as often as he's throwing any of his other pitches. We can only assume that's partly because he just likes watching it move.

    Rob Friedman @PitchingNinja

    Shohei Ohtani, Vicious 83mph Sweeper. 😤<br><br>And Fist Pump. 💪<br><br>8th K <a href="https://t.co/knF35wMlM3">pic.twitter.com/knF35wMlM3</a>

    Knowing that the difference between a sweeper and a traditional slider really is all about horizontal movement, it's no surprise that Ohtani has become the face of the wider, um, movement toward the pitch this season.

    On average, he's putting 3.5 more inches of lateral movement toward his glove side on his sweeper than he was in 2022. More than half (112, to be exact) of the 210 he's thrown have yielded called strikes, fouls or whiffs, with only eight getting hit for hard contact.

    Ultimately, opposing batters are just 3-for-48 against the Los Angeles Angels star's signature pitch. That's an .063 average that's far and away the best for any pitch that's ended at least 40 plate appearances.

Spencer Strider's Slider

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    ATLANTA, GA - APRIL 12: Spencer Strider #99 of the Atlanta Braves pitches during the first inning against the Cincinnati Reds at Truist Park on April 12, 2023 in Atlanta, Georgia. (Photo by Todd Kirkland/Getty Images)
    Todd Kirkland/Getty Images

    Key Stat: Its .111 xBA is the lowest among pitches that have ended 40-plus plate appearances.

    Shouldn't this say Spencer Strider's four-seam fastball? That is what the Atlanta right-hander is known for, is it not?

    Technically yes, and deservedly so given that his fastball was responsible for 120 of the 202 strikeouts he racked up in his sensational rookie season last year. But his slider is playing a bigger role for him in 2023 and this, too, is a "deservedly so" situation.

    Rob Friedman @PitchingNinja

    Spencer Strider, Wicked 86mph Slider. 🤢<br><br>9th K <a href="https://t.co/RoJtZebBO5">pic.twitter.com/RoJtZebBO5</a>

    Strider has upped his slider usage from 28.2 to 32.6 percent and is clearly reaping the benefits. The whiff and strikeout rates on the pitch are both in the 50 percent range.

    Though Strider's slider is coming in 1.5 mph slower on average than it did in 2022, the trade-off there is more downward movement. He's also been better about locating it in the "shadow" of the strike zone, where it's harder for opposing hitters to lay off it.

    So dominant has Strider been with his slider that it's a bit of an injustice that batters are even 2-for-26 against it. Both hits were bloop shots whose exit velocity averaged out to 69.8 mph.

Nick Lodolo's Curveball

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    Cincinnati Reds starting pitcher Nick Lodolo delivers during the first inning of a baseball game against the Pittsburgh Pirates, Saturday, April 1, 2023, in Cincinnati. (AP Photo/Joshua A. Bickel)
    AP Photo/Joshua A. Bickel

    Key Stat: It's drawn 24 swings in "chase" and "waste" regions, and 23 have missed.

    It is with since apologies to Phil Maton that we opted to put somebody else's curveball here. His is a high-spin demon against which batters are 0-for-17 with seven strikeouts.

    But, well, can anyone really blame us for being mesmerized by the back-foot-seeking sidewinder thrown by Cincinnati Reds left-hander Nick Lodolo?

    Rob Friedman @PitchingNinja

    Nick Lodolo, Ridiculous 91mph Breaking Ball. 😲<br><br>Yet again getting a swing at a pitch that ends up behind a hitter. <a href="https://t.co/V3qSRW3Mmh">pic.twitter.com/V3qSRW3Mmh</a>

    Kudos to nobody but Philadelphia Phillies utility man Josh Harrison. Of the 24 swings taken at curveballs that Lodolo has put in the "chase" and "waste" regions of the zone, his foul ball on April 8 is the only one that wasn't a swing and a miss.

    A number of things make Lodolo's hook such an effective eviscerator of major league hitters. He throws from a low arm slot relative to other southpaws, and the pitch itself is characterized by good velocity (79.2 mph) and glove-side movement (15.4 inches).

    It's basically a more extreme version of Framber Valdez's curveball. And while batters may be a respectable 8-for-34 against it, only three of those hits were 95-plus mph off the bat.

    Honorable Mention: Charlie Morton, Atlanta

Shane McClanahan's Changeup

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    Tampa Bay Rays starting pitcher Shane McClanahan throws to a Boston Red Sox batter during the first inning of a baseball game Tuesday, April 11, 2023, in St. Petersburg, Fla. (AP Photo/Scott Audette)
    AP Photo/Scott Audette

    Key Stat: Its 58.2 percent whiff rate is the highest of any pitch that's been swung at 50 or more times.

    If Shane McClanahan likes swings and misses in the best of times, then he's clearly determined to make 2023 the bestest of times.

    His start opposite the Chicago White Sox on Saturday saw him become the first pitcher in the pitch-tracking era to record as many as 32 whiffs on fewer than 100 total pitches. He boasts a league-leading 100 whiffs for the season, with 39 of those coming on his changeup.

    In defense of the hitters who took those 39 swings, there is no good advice for how to hit something like this:

    Rob Friedman @PitchingNinja

    Shane McClanahan, Vicious 86mph Changeup. 👌<br><br>8th K. <a href="https://t.co/KJQ3hRNSTo">pic.twitter.com/KJQ3hRNSTo</a>

    The Rays lefty has sacrificed some velocity on his changeup this year, but for good causes. It now features a career-best 16.6 inches of arm-side movement on average, while the velocity differential between his change and fastball is up to 9.6 mph from 9.0 mph in 2022.

    It's thus not surprising that batters have all of four hard-hit balls against the 111 changeups McClanahan has so far. It's basically impossible to be both on time and on target against it.

Kevin Gausman's Splitter

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    TORONTO, ON - APRIL 12: Toronto Blue Jays Pitcher Kevin Gausman (34) throws a pitch during the MLB baseball regular season game between the Detroit Tigers and the Toronto Blue Jays on April 12, 2023, at Rogers Centre in Toronto, ON, Canada. (Photo by Julian Avram/Icon Sportswire via Getty Images)
    Julian Avram/Icon Sportswire via Getty Images

    Key Stats: It leads all pitches with 46 swings and misses and 25 strikeouts.

    Yes, Félix Bautista's splitter is still out there. And yes, its 66.7 whiff rate is the best of any pitch if the bar is set to 25 swings.

    But until further notice, Toronto Blue Jays right-hander Kevin Gausman is still MLB's foremost splitter maestro. Those numbers up there pretty much speak for themselves, and it's for danged sure still pretty to look at:

    Rob Friedman @PitchingNinja

    More of Kevin Gausman's Impossible Splitters. <a href="https://t.co/uTZUvMNmXF">pic.twitter.com/uTZUvMNmXF</a>

    Gausman is throwing the splitter a career-high 39.2 percent of the time in 2023, so batters know it's coming just in a general way. They especially know it's coming if he has two strikes, as he's throwing it 60.4 percent of the time in those spots.

    Why can't they hit it anyway? Partly because he's putting more arm-side movement on it than ever before, and also partly because he's doing a better job of keeping it down.

    Simply not swinging at Gausman's splitter is the best hope hitters have of not getting beat by it. Because even in the 22 occasions in which they've put it in play, only four resulted in hard-hit balls.

    Honorable Mention: Jhoan Duran, Minnesota Twins

Kodai Senga's Forkball

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    New York Mets pitcher Kodai Senga throws to a San Francisco Giants batter during the first inning of a baseball game in San Francisco, Thursday, April 20, 2023. (AP Photo/Tony Avelar)
    AP Photo/Tony Avelar

    Key Stat: Its .124 xSLG is the lowest for any pitch that's ended at least 25 plate appearances.

    What's the difference between a splitter and a forkball? It's mostly in the grip.

    Though both pitches are gripped between the index and middle fingers, the splitter rests closer to a pitcher's fingertips. The forkball is wedged deeper in the gap between the two fingers and thrown with a snap of the wrist.

    Mind you, this is just for a regular forkball. Kodai Senga's "ghost" fork is a beast of a different sort and has surely played as such through his first four outings for the New York Mets.

    Rob Friedman @PitchingNinja

    Kodai Senga, Disappearing 82mph Ghost Fork. 👻🍴<br><br>792 RPMs. <a href="https://t.co/qzaoZ1S163">pic.twitter.com/qzaoZ1S163</a>

    The characteristics of Senga's forkball are essentially the opposite of those of his fastball. Whereas the latter is a high-velocity, high-spin offering with rising action, the former is a relatively low-velocity, low-spin pitch with steep downward action.

    As it's a pitch that truly seems to disappear at the hitting zone, its moniker is well earned. And likewise for its early success, as it's just plain hard to fake a line that has just three singles and 17 strikeouts out of 25 at-bats.

    Honorable Mention: Only Senga throws the forkball, so nobody.