Lucas Giolito Isn’t Quite Right

Lucas Giolito hasn't looked like himself in 2021. That could change.

Lucas Giolito is one of my favorite stories in baseball. In 2018, he was the worst qualified starting pitcher in Major League Baseball, and then from 2019 to 2020, he was one of the best. It’s not a secret that his growth can be traced back to a drastic change in his arm circle and fastball velocity — and those things have continued to hold — but we’re more than a month into the 2021 season now, and Giolito doesn’t look quite like himself.

On the surface, everything looks okay. Giolito has mostly maintained his fastball shape and velocity, and his pitch mix has remained constant from last year, too. For the most part, it’s just his peripherals are just … off. There’s nothing in particular that sticks out. He’s been getting hit harder than ever — which has led to more home runs — and he’s been struggling to strike hitters out. Given that those components make up two-thirds of FIP, you can imagine that his FIP- has fallen by about 30 points from the past two years. Whereas he was in the low 70s in 2019 and 2020, his 101 FIP- in 2021 essentially tabs him as a league-average pitcher. That’s obviously subject to change — and this isn’t an unprecedented low for Giolito — but for the time being, it’s certainly worrisome.

Consider Giolito’s seven-game rolling strikeout percentage and hard percentage:

With the advent of Statcast, FanGraphs’ hard percentage doesn’t mean so much to us anymore. But when in conjunction with Baseball Savant’s hard-hit percentage, barrel percentage, and xwOBAcon, it’s clear that Giolito is getting hit as hard as he ever has before — and that’s including his 2016 to 2018 seasons. The strikeouts are still there — and I’d certainly consider his strikeout percentage good — but Giolito is a pitcher who already walks more hitters than is typical, so he can’t afford to lose strikeouts like, say, Zack Wheeler can.

That, of course, begs the question: Where have the strikeouts gone? And why is he getting hit hard? Although it may not seem all that clear at first, my hypothesis isn’t very complicated.

Giolito’s average vertical release point, from 2016 to 2021:

Now, generally speaking, it’s good to be on the extreme end of things. The weirder the look you give hitters, the harder it is on them. Throwing over the top? Good, if you can do it. Knuckles scraping on the mound? Also good! Giolito still has one of the highest release points in baseball, but it seems like he’s dropped ton a fair amount.

Here are representative release points from Giolito, from 2019 to 2021:

It should be clear that, despite being in the same park, these camera angles aren’t identical. Within the season, camera angles change. Between seasons, they’re even more subject to change. Given this, I’m at the mercy of the White Sox camera crew. If we’re to try and scrutinize some deeply flawed screenshots, maybe we see Giolito hinging less to his left side, and maybe we see his arm drop down and out because of that. It doesn’t seem that he’s shifted significantly on the rubber, so all that’s left is to cross-reference his actual release points, visually.

Again, from 2019 to 2021, Giolito’s release points:


This feels much more conclusive. It is much more conclusive! When you’re seeing a shift on the rubber, you should only see the cluster of release points drift horizontally. Here, it’s evident that Giolito’s release point has drifted to his arm-side, but it’s also dropped down by a few inches too. That indicates that this is probably less about Giolito’s position on the rubber, and much more about his arm slot, which has dropped. It might feel minor, but it leads me to believe that this has had an effect on the way that Giolito’s pitches behave.

Generally speaking, the more on the side of the ball you get, the more side-to-side movement you get. Pitchers on the extremes often locate east-west. Get on the top of the ball, and your pitches start looking more like James Karinchak’s. Those pitchers locate north-south, like Giolito historically has. If you consider the spin direction of Giolito’s pitches in the format of a clock, all of them have shifted clockwise. Giolito’s fastball hasn’t changed much, but his changeups (yes, plural!), have gotten more arm-side movement, and a little more drop. His slider, though, has dropped pretty drastically.

Given the heavy gyro component of Giolito’s slider (i.e., it spins much like a bullet), it’s subject to a relatively wide range of horizontal movement. Sometimes, gyro sliders will move glove-side, as is typical, but sometimes they’ll move arm-side too. Giolito had more than a few drift arm-side in 2019, and a few in 2020 too, but this year, his slider’s shape has been as variable as ever.

Giolito’s pitch movement, from 2019 to 2021:

Focus on his 2021 slider. It’s completely lost the consistency in movement that it had in previous years. Given the interaction of Giolito’s new arm slot and the movement of his pitches, I posited that his pitches would all drift arm-side. In general, that seems to be the case. The location of his fastball and changeup are both a touch more arm-side than last year, which means that his fastball is ending up in the upper-middle or center-middle portion of the plate. I have a hard time believing that that’s by design, and so the command of his pitches appears to be eluding Giolito at this moment in time. All of Giolito’s pitches are getting hit harder — his fastball in particular — and I think that’s closely related to his command.

Most blatantly, though, Giolito doesn’t have his slider. Consider the location of his 2019 and 2020 sliders against his 2021 sliders:

Before, Giolito would pepper the edge of the strike zone on his glove-side against lefties and righties alike. He still does sometimes, but he’s more likely to miss out over the plate, or spike a pitch a slider in the dirt. Obviously, given that he has a good fastball and two variations of a plus changeup, he’s able to mitigate the inconvenience of a three-pitch pitcher effectively losing one of his pitches, but his struggles have been compounded by the ostensible command woes of his other offerings as well.

It seems clear that this comes down to Giolito not being able to put the ball where he wants to put it. He’s never been a command darling, but his command has taken a step back for the time being, and that’s affecting the potency of his offerings. His fastball is getting torched more than a fastball its shape and velocity should, and we should probably see Giolito right himself before long. He was too good for too long to think that this should sustain itself for much longer. He’s missing something like half a tick of fastball velocity, but perhaps what he’s missing more is his old release point.

(Photo by Quinn Harris/Icon Sportswire | Design by Michael Packard (@designsbypack on Twitter @ IG)

Michael Ajeto

Michael writes about the Mariners at Lookout Landing, as well as here at Pitcher List. You can follow Michael on Twitter @dysthymikey, or you can not.

3 responses to “Lucas Giolito Isn’t Quite Right”

  1. Brian Holcomb says:

    Awesome article. Having drafted Giolito, I’ve been especially involved in watching his starts (wow the 7th inning of that Tigers start was infuriating!). Really interesting to learn the source of his challenges right now. Hope he gets his 2019-2020 groove back soon!

  2. Harry Lime says:

    Timely article Michael. Makes watching his next start all the more interesting.
    Good work. More pls!!!

  3. Jason says:

    A+ analysis and writing.

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