Tyler Glasnow Sliding Into the Cy Young Conversation

Tyler Glasnow's new 'slutter' is wreaking havoc on the American League.

Every spring, as pitchers and catcher report to Florida and Arizona – and then the position players follow closely behind – baseball fans are greeted with endless “Best Shape of His Life” stories. Spring training blurbs and quotes chronicling the different players (usually ones who had struggled the year prior) who have re-dedicated themselves over the winter and gotten into tremendous physical shape in hopes of having a bounce-back season. This BSOHL phenomenon has taken on a life of its own in recent seasons and currently has a poster boy in Toronto who is in the midst of a true breakout season, currently hitting .383 with a 1.163 OPS.

The parallel to this for pitchers is the “tinkering with a new grip” or “adding a new pitch” storylines where we learn about different pitchers who have used the offseason to add a new weapon to their arsenal for the upcoming season. More often than not, the newly-minted addition to their repertoire ends up either on the cutting room floor or being so seldomly used that it goes virtually unnoticed.

This is not the case with the 2021 version of Rays ace Tyler Glasnow

For the past few years, Glasnow has been featured regularly on the daily “Nastiest Pitches” articles here at Pitcher List thanks to his knee-buckling 12-to-6 curveball and overpowering 98-99 mph fastball, a lethal combination that propelled him to a 6-1 record with a 1.78 ERA and 0.89 WHIP in 2019. In fact, Glasnow’s curveball recorded the third most strikeouts of any single pitch (58) in 2020, trailing only Dinelson Lamet’s slider and Framber Valdez’s curveball.


That curveball is a thing of beauty – one of the best pitches in baseball. And when paired with an elite fastball, the result is often that of a hitter turning and slowly walking back to the dugout (see below).

Gotta love that K strut.

As part of a previous article I wrote earlier this offseason, I referenced the following table when I was discussing Dinelson Lamet and his unique over-reliance on his slider as his primary pitch. When pulling the data for the table, however, it was Tyler Glasnow who jumped off the page at me, as his reliance on his heater in 2020 was staggering.


The 6″8′ towering right-hander has been able to thrive despite the lack of a third pitch, using his height to his advantage in a way that Randy Johnson was able to 20+ years ago. Glasnow has pitched effectively despite the over-reliance on his high-90’s fastball because hitters barely have time to react to the pitch with that type velocity coming downhill at them with his wingspan and release point from a pitcher of Glasnow’s height.

No doubt that Glasnow and the analytically-driven Rays organization have been well aware of these trends and usage patterns, however, especially in light of Glasnow’s relative struggles (4.08 ERA) during the abbreviated 2020 season. In an appearance earlier this month on FOX’s Flippin’ Bats podcast with Ben Verlander, Glasnow had this to say about the addition of a new pitch:

Glasnow: “It came out of necessity I think. Once you fail enough with two pitches – not really fail enough – but really I had two pitches and….sometimes it’s not gonna work out. Sometimes you’re gonna have a heater, sometimes you’re gonna have your curveball, sometimes you’re gonna have both, sometimes you’re gonna have neither, and it was just a limited amount of options for me and when I had one pitch that was off, it was everyone in the ballpark knew what was coming…you could sell out to heaters and it doesn’t matter how fast you throw in the big leagues, guys are gonna hit your heater, it doesn’t matter….I needed to have a third pitch.” 

So this offseason, Glasnow went “back to the lab” as he calls it, working with Rays pitching coach Kyle Snyder, and found something that should have American League hitters losing sleep at night.




Tyler Glasnow’s Pitch Mix 2019-2021

Glasnow was virtually a two-pitch pitcher in 2019-2020, and the fact that he’s been as successful as he has in that timeframe tells you just how special those two pitches truly are. Not unlike the aforementioned Lamet last year in San Diego, who relied primarily on his fastball-slider combination.

In 2021, Glasnow is still relying heavily on the four-seam fastball – more than most in fact –  but he’s now added a new “slutter” as he calls it – a slider/cutter combo that breaks away from righties and in on lefties. Baseball Savant tracks the pitch as a slider which has worked as an alternative to his curveball, especially to right-handed batters (70 of his 111 ’sliders’ to date – 63% – have been to righties).

  • Avg. velocity of his fastball: 97.2 mph
  • Avg. velocity of his curveball: 83.6 mph
  • Avg. velocity of his slider: 87.6 mph

The slider, or slutter if you prefer, with four extra mph of velocity compared to the curveball, is proving to be a terrific compliment nestled in between the speeds of his fastball-curveball combo platter and has given the Rays flamethrower a quality third pitch that separates the good starters from the great ones.

His curveball has always been his go-to, put-away pitch, but he’s been able to rely on it less this season due to the incorporation of the new slider:

  • 52% whiff percentage in 2021, 53% in 2020 with the curveball
  • 39.0 % put-away percentage in 2021, 36.0% in 2020 with the curveball

And the results have been deGromian.

The slutter has been incredibly effective for Glasnow, as hitters are hitting just .176 against it with a 39.1 whiff percentage, which has allowed him to use it so frequently. It’s quite remarkable to see a pitcher go from never using a pitch in 2019-2020 to it becoming his second-most thrown pitch (29.1%) in 2021. It’s not as dominant as his curveball or his fastball, but it doesn’t need to be.


The following tweet from the incomparable Rob Friedman – better known as the Pitching Ninja (@PitchingNinja) – shows Glasnow striking out Giancarlo Stanton this past Saturday with the slutter – and then shows a follow-up overlay video illustrating the similarity between the fastball and the slutter before its break point, making it nearly impossible for hitters to distinguish the difference between the two.

Glasnow is 2-0 through four starts with a Statcast page that features more red than a packed house at Busch Stadium when Cincinnati is in town. He’s also currently tied with Brewers ace Corbin Burnes as the leader in WAR this season (via FanGraphs) at 1.4.

  • 0.73 ERA
  • 0.65 WHIP
  • .138 xBA
  • .190 xSLG
  • .152 xwOBA
  • .248 wxOBAcon
  • 40% K percentage
  • 1.25 xERA
  • 13.14 K/9
  • 36% CSW
  • 18.1% SwStr%

Glasnow is tied with Trevor Bauer for fifth in the league in strikeouts. He’s allowed only two runs total and is yet to allow a home run this season. Amazingly, he’s only allowed one barrel. Hitters used to be able to try to hone in on the high-90s fastball while trying to lay off the curveball. But with a newly incorporated slider that comes from the same arm action as the fastball, hitters have proven to be helpless.


Tyler Glasnow’s 2021 Game Log


Watch that clip above from Jordan Moore (@iJordanMoore) and it becomes impossible to argue that Glasnow doesn’t possess the arsenal to be amongst the best pitchers in baseball – and right in the thick of the AL Cy Young conversation. And while that third start against Texas was sensational when he struck out a career-high 14 batters, I was perhaps most encouraged by his most recent start this past weekend against the Yankees.

The reason I say this is because Glasnow wasn’t sharp. At all. In fact, he was quite erratic. He didn’t have command early on and ended up walking more batters than he had in his previous three starts combined. He was constantly missing high with his curveball, uncorked a wild pitch, and simply did not have a great feel for his pitches, specifically his off-speed stuff. Glasnow even had to pause the game due to a bizarre cramp in his non-pitching hand at one point in the middle innings. And yet, he yielded only one run through five frames and struck out seven. He battled through when his stuff wasn’t at its best, retired 11 of the final 12 batters he faced, and found a way to emerge victorious. No doubt that the addition of a viable third offering made this possible.

This was the type of outing in years past that would have usually led to a crooked number on the scoreboard for Glasnow. But in 2021, the 27-year-old remain focused and secured his second win of the season. If he’s capable of that type of performance on a day where he doesn’t have his command, the American League is in big, big trouble.

Winning a Cy Young award will certainly prove to be a tall task for Glasnow (pun very much intended). Shane Bieber and Gerritt Cole aren’t going anywhere, and Glasnow pitches in a tough division where he will regularly be pitching against the likes of the Yankees (is that such a bad thing?), the Red Sox, and the Blue Jays. All tough offenses.

He’s also been historically one of the easier pitchers in baseball to steal bases against (along with Noah Syndergaard). From 2018-2020, Glasnow allowed 39 steals in 49 attempts (79.6% success rate). He’s already allowed two steals this season, and that’s with very few batters even getting on base.

Nonetheless, the incorporation of a bonafide third pitch to join the fastball/curveball party is proving to be a breakthrough development for the former Pirate. And a terrifying development for hitters in the Junior Circuit.

Next up: the Toronto Blue Jays on Friday. Good luck.



Photos from Cliff Welch/Icon Sportswire and Library of Congress | Design by Quincey Dong (@threerundong on Twitter)


Lucas Spence

Writer for Pitcher List and contributor for FantasyPros and InStreetClothes whose favorite baseball highlight of his lifetime occurred in the bottom of the 11th inning of the 1995 ALDS. Twitter: @lspence24.

One response to “Tyler Glasnow Sliding Into the Cy Young Conversation”

  1. DB says:

    I mean… fine, be a fan of a team, out loud and up front, but when you’re writing for a site that covers all of them, don’t yuck on some of your readers’ yum. (RE: Yankees comments.)

    Go figure, a W.E.E. GIF… shocker: a person that likes staged and scripted competition doesn’t like a good baseball team.

    Do me a favor pitcherlist, and don’t hire people like this guy any more.

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