Why Griffin Jax is Adding a Cutter

Mar 14, 2023 - 1:15 PM

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One of the most common refrains we hear about players coming into Spring Training is that they are “in the best shape of their life”. Those reports fuel optimism about a pending breakout or a veteran return to form, depending on the circumstances.

The past few off-seasons have seen a new trend pop up in the Spring Training reports, especially for pitchers. Namely, “he went to Driveline,” the data-driven player development laboratory where pitchers go into the laboratory to experiment with their stuff.

Dan Hayes recently had the story of four Twins pitchers making the trek to Driveline this off-season to improve their crafts. Caleb Thielbar’s career renaissance is attributable in some measure to his work at Driveline and he went in for a tune-up. Joe Ryan and Tyler Mahle visited with hopes of finding higher-quality secondary stuff to accompany their deceptive fastballs, especially the bigger breaking sliders that Ryan had already started to tinker with last season.

Griffin Jax, already the owner of a devastating sweeping slider (that he taught to Ryan late last season, per Hayes) and fully invested in his role as a relief pitcher, focused on his mechanics to try to add fastball velocity and on adding a new pitch to his arsenal: a cutter.

Why Sweepers?

Sweeping sliders have become all the rage among pitchers over the past couple of seasons. Many organizations, led by the Dodgers and Yankees, and individual pitchers have worked to add and perfect them. So much so that a few weeks ago the folks at Baseball Savant made a “sweeper’ a distinct pitch classification.

Accurate classification of pitch types is an inherently messy business (what one pitcher calls a slider, another pitcher might call a curveball, for example), but the Savant data shows the number of sweepers thrown across the game has increased from just a couple of hundred in 2017 to nearly 9,000 last year. If Spring Training news headlines about pitchers working on new pitches are to be believed, that figure is sure to increase significantly more in the coming season.

A big part of the appeal of the sweeper, besides the aesthetic of a big-bending breaking pitch, is that they tend to suppress production on contact. Like “normal” sliders, they are most useful against same-sided hitters, and sweepers miss bats and allow home runs at roughly the same rates as regular sliders. But when a sweeper is put in play, it’s much more likely than a normal slider to be a weakly hit pop-up, instead of a ground ball. While ground balls are great, they sometimes turn into singles, and pop-ups, which almost always turn into outs, are even better.

Griffin Jax’s Arsenal

Jax calls his main breaking ball a slider, but it has many of the hallmarks of a sweeper thanks to its incredible movement profile at its 86.4 mph average velocity. Jax ranked second in all of baseball last season in horizontal movement above average at that speed. His vertical drop with the pitch was about 12% more than average at that velocity, giving him a unique two-plane breaking pitch:

Baseball Savant

(Side note: That farthest down and to the right yellow dot belongs to Sonny Gray)

Jax rode his slider hard, throwing it as his primary pitch (48.4%). It was successful, with opponents hitting just .187 slugging just .260 against it. They whiffed 36.8% of the time they attempted to swing at it. By the pitch quality modeling data that was just released at FanGraphs last week, Jax’s slider was the 4th best among qualified relievers via PitchingBot (71 on the 20-80 scouting scale) and 11th-best by Stuff+ (140, against a 100 average).

The other pitches in Jax’s tool kit are more average than they are standout. He works with his four-seamer (33.7%) most often after the slider, but also mixes in the occasional changeup (13.7%) and curveball (4.2%), usually to left-handed hitters. Each of these three other pitch types grades out as more or less average by a number of different methods for assessing such things.

He pushed his average four-seam fastball velocity up above 95 mph with the move to the bullpen last season. That contributed to a different movement profile (less drop, less horizontal movement), but the pitch yielded +1.9 runs per Statcast graded out as a just-below-average 97 by Stuff+ and a just-above-average 53 by PitchingBot. Opponents batted .258 and slugged a whopping .530 against it and half of the 16 extra-base hits Jax allowed came off four-seamers, including 5 of the 7 home runs he gave up. Opponents swung and missed at Jax’s fastball 19.3% of the times they swung at it, a well below-average rate for a reliever.

While Jax has a former’s starter’s arsenal, it’s primarily the fastball-slider pairing where he makes his living out of the bullpen. For him to make another step up the leverage ladder, he will need to do something about his fastball.

Developing for the Future

Adding more velocity is one way to help that pitch improve going forward, another way might be to add an additional pitch type.

Recent research about pitch tunneling from Ethan Rendon, Elijah Emery, Will Sugar, and Tieran Alexander writing at ProspectsLive has been able to put some numbers to the optimal pitch shapes for tunneling and how to make life more difficult for hitters.

Regarding the pairing of fastballs and sliders, they found the following basic rules about how the movement profiles of the two pitches should differ from one another:

• 6 to 14 inches of horizontal movement separation
• 8 to 16 inches of induced vertical break separation
• 6 to 11 MPH velocity separation

Jax hits the mark in terms of velocity differential, with 9 miles per hour separating his fastball and slider. But his movement separation is greater than optimal, both horizontally and vertically.

Jax’s slider averaged about 11.4 inches of horizontal movement to his glove side and his four-seamer averaged about 8.6 inches of horizontal movement to his arm side, giving him an average horizontal separation of about 20 inches between the two pitches last season.

After adjusting to remove the effects of gravity, known as induced vertical break, Jax’s slider moved about 1.8 inches downward and his four-seamer moved about 16.7 inches upward for a total average vertical separation of 18.5 inches.

Enter A Cutter

So, what can pitchers do if they have too much movement separation between their fastball and their slider?

One option is to try to change the movements of those pitches to be tighter together. In Jax’s case, that seems inadvisable given the quality of the slider and the fact that he’s already throwing a typically less-horizontal breaking four-seamer, instead of a sinker.

Another option, which is growing in popularity as a tool for guys who are throwing sweepers, is to add a cutter with a movement and velocity profile that sits in between the four-seamer and the sweeping slider.

In Jax’s pitch movement map above there is a lot of white space between the yellow and red plots. Somewhere in that gap is where Jax’s new cutter will live, along with low-90s velocity.

For pitchers that have extreme amounts of vertical and horizontal separation, mixing in a cutter has become a common remedy because it gives the pitcher something to bridge the movement gap and adds an offering that is more likely to stay on the plate.

San Diego’s Yu Darvish might be the most prominent example of a pitcher with wicked movement profiles on his fastball and breaking balls who uses a cutter to steal strikes and tunnel something in between the fastball and slider to keep hitters off balance. Darvish’s cutter alone doesn’t get superlative results (.376 wOBA allowed last year), but it serves a greater purpose within his arsenal and helps his other offerings play up.

Seattle’s Matt Brash, the only pitcher who outdid Jax in horizontal slider movement above average last season, spent much of this winter working to add a cutter to his mix for some of the same reasons. As the writers from ProspectsLive put it, “the fastball and slider don’t have to look the same, they just have to look like the cutter, which looks like both of them.”

This video clip from Brash’s work at Driveline, especially the three-pitch fastball-cutter-slide overlay at the end, illustrates the intended effect well:

The most important part of adding a cutter for Jax is going to be throwing it for strikes, as he told Hayes. “When I started to throw lives, I just wanted to get it in the zone. I didn’t care really where it was. But as long as I could throw it for strikes, that’s the biggest thing. … Saw that a lot. I was able to put it in spots where if they swung they were swinging and missing or they were good misses.”

Like any new offering, it will take some time and repetition to get it where it needs to be. Jax has admitted this spring that the cutter’s shape can be “a little inconsistent from day to day”. Nonetheless, he’s proven before to be adept at spinning the baseball and picking up new pitches.

If he’s able to master the pitch, it’s got a good chance to elevate his entire arsenal. It could give him another option when he needs to get a strike, which should help keep hitters off his fastball and continue to chase his slider. A cutter might also be a useful weapon against left-handed batters, which Jax suggested was also part of the motivation for adding the pitch. With the Twins holding tight on their bullpen personnel this off-season, any steps forward from last season’s success from Griffin Jax will be a welcome addition.

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John is a writer for Twinkie Town and Pitcher List with an emphasis on analysis. He is a lifelong Twins fan and former college pitcher. You can follow him on Twitter @JohnFoley_21.