"Did That Cut?" An Intro to Cutters

In today's post Adam Schuck covers the basics surrounding what makes a good Cutter. In doing so, he will have to dive into the legitimacy of a phrase used too often in the bullpen - "Did that cut?"

One of my biggest pet peeves, and seemingly a large misunderstanding from many pitchers, is identifying cut - or glove-side break. If you sit back and watch a bullpen session, pitchers will work in and out with their pitches trying to hit spots. Oftentimes, pitcher’s may miss their spot to their glove-side and immediately ask the catcher, “Did that cut?”...“Yeah that was weird, you just got around that one,” is something you may hear from the catcher. But in fact, no it probably did not. It’s likely just your eyes playing tricks on you. Today we are going to dive in a bit deeper into the common misconception of “cut”, define pitches that actually cut, and discuss what Cutters are good for.

Spin Efficiency

There have been quite a few pieces on Spin Efficiency on the SS channel so far (example here). As a quick refresher, Spin Efficiency is the measure of how much spin imparted on the ball is affecting the movement of the pitch. Not all spin affects movement since gyro spin, or bullet spin, does not contribute to movement. Unless you are a freak of nature (I’m sure they exist somewhere), every pitch with cut has some combination of back spin (creates hop/ride) or top spin (creates depth), side spin (creates lateral sweep), and gyro spin (bullet spin).

Most Fastballs are dominated by back spin with a moderate amount of side spin and a hint of gyro spin. Sliders on the other hand are dominated by gyro spin with moderate amounts of side spin (the opposite direction of Fastballs) and a touch of top or back spin. What makes Cutters unique is that they are much closer to equal parts of all 3 types of spin with components of back spin, gyro spin, and a smaller portion of side spin.

If you were going to throw a pitch with cut and without gyro spin you would have to come around the ball spinning it like a frisbee or come so far over the top you are on the other side of the ball like an opposite handed pitcher would throw a Fastball. Like this pitch from James Karinchak.


Throwing a Fastball like Karinchak is not something most people can do, so to generate cut we need to come around the ball a little bit to create an axis around 11:30 (12:30 for LHP) and a small amount of sidespin and additional gyro spin. Below is the intended shift from your typical fastball that we are looking for.

In order to create this shift we must change the way we are releasing each pitch. That may come from a change in grip, or simply the way that pitch is released. Below is a video that starts by showing you a typical Fastball. Then, an intended Cutter that lowers spin efficiency but never shifts the axis to create lateral break. And finally, a correctly executed Cutter that kills lift and creates lateral break.

The first clip is probably what you would imagine a Fastball looks like. The pitcher stays behind the ball, inducing very little to no gyro spin with a Spin Direction creating just a bit of arm side run. In the second clip, the pitcher does a good job inducing some gyro spin, but is never able to shift the axis away from the Fastball’s axis as he is still too far behind the ball. In the third clip, the pitcher is able to successful induce both gyro spin and lateral break by tilting the axis to roughly 11:30. As you can see, there is a fairly significant change from even a 12:30 to the necessary < 12:00 axis needed to create cut, let alone from an average 1:30 to <12:00. This isn’t something that can just happen by accident.

What can a Cutter do for me?

Above is a summary of all pitches and batter/pitcher handedness matchups in 2019 at the MLB level from publicly available Baseball Savant Data. You’ll notice that Fastballs typically perform the worst followed by Breaking Balls and Changeups. Well where do Cutters lie? They are sort of a middle of the road pitch in terms of their performance against the population. They generate a significantly lower xwOBA than Four Seamers while inducing more whiffs and ground balls, however not quite on the level of effectiveness as Breaking Balls or Changeups.

As always, there are outliers who throw very hard and outperform the average (ie Kenley Jansen, Mariano Rivera, etc), but most people don’t get away with having a Cutter as their primary pitch or even their main secondary offering. It’s a pitch that is so similar to the Fastball in terms of batter timing that unless it is overpowering in its velocity and movement profile, it’s a bit easier to "stay on" compared to the Changeup or Breaking Balls. Typically, it is a situational pitch used to tunnel off the previous Fastball with the hopes of inducing weak contact or a whiff by just missing the barrel. You'll notice they are much more effective against in a same-handed matchup. Much like the gyroball in my last article, Cutter's are a good gap pitch. However, gyroballs are more for filling a vertical plane gap in your arsenal while Cutters are more for adding a horizontal element your arsenal may be lacking (ie. pitchers with high riding Fastballs and big depthy Curveballs).

(All Pitches are flipped to mimic a RHP)

Unlike most other pitches, there isn’t a ton of deviation in Cutter movement from pitcher to pitcher. The spread of movement profiles is much tighter on the Cutter (5-15 VB/ 0-6 HB) compared to other pitches with as much as a 20 inch range either direction. From the plot above, no one movement profile really seems to be much better or worse than another via xwOBA. If you’re unfamiliar with movements plot please check out this brief explanation!

It would make sense to me that Cutters closer to a pitcher's Fastball velocity would likely be more effective, but that doesn't seem to be entirely true either. Most variable's plots whether it be raw velocity, horizontal separation from the Fastball, etc all don't have clear trends when compared to CSW or xwOBA. As of now, I'm not really sure what makes a Cutter "good" according to available data. Late movement? Looks like the Fastball until it's not? Those are my two best guesses but right now, but those aren't things easily measurable.

Did That Cut?

Now that we understand what makes a pitch cut, let’s revisit our title, “Did That Cut?”. In the plot below, Fastballs are blue and pitches auto-classified as Cutters are red. For a pitch to actually cut, it would need to end up on the left side of the movement plot (indicating glove-side movement), not on the right side. Unless you are a pitcher whose Fastball is frequently around a 12:00 axis, there is little to no chance you are accidentally getting horizontal break on the other side of the y-axis on your fastballs.

(All Pitches are flipped to mimic a RHP)

Now what is most likely happening is your Fastball is regularly around 1:30 and one happened to slip out around 1:00. This would have significantly less run than a pitch on a 1:30 axis, possibly appearing to “cut” to the catcher, when in reality it just has less run than usual. Often, the same situation may occur when throwing glove-side vs arm-side. When throwing arm-side, you release the pitch on a trajectory directly in your line of sight towards the plate. So, the pitch appears to be straight and then take off arm-side. If you throw the exact same pitch glove-side, it will appear to be straighter due to the initial trajectory of the ball being further away from your line of sight and then coming back towards it. In reality, the two pitches move very, very similarly. Take Dustin May for example, throwing two Sinkers with near identical movement profiles.

You'll notice that the second video appears to have less horizontal movement than the first despite actually having nearly exactly the same (18in vs 19in). It’s my opinion that incorrectly identifying cut can be harmful to a pitcher as it doesn’t paint a clear picture as to what is actually happening and may lead to attempted changes that don't need to happen.

If I were to accidentally cut the ball, I would be getting around the ball a significant amount to create an element of sidespin. If I really just threw a pitch straighter than usual then it’s likely I’m actually getting further inside the ball than I normally do. Two completely different issues being mistaken for the same thing. Most of us have access to some sort of pitch tracking device now and can easily use that for feedback on a pitch by pitch basis. If your pitch tracking device says the ball had arm-side run, and your slow motion video doesn’t show any type of axis shift, then your pitcher has probably fallen into one of the misconceptions above.

Wrapping Up

What is cut? Induced side spin the opposite direction of your Fastball. If you have a Fastball with positive horizontal break, a pitch with cut would have negative horizontal break on a movement plot.

What are Cutters good for? Cutters are most effective in a same handed matchup to induce weak contact.

Did that cut? Eh, probably just your eyes playing tricks on you. But, double check your pitch tracking device and slow motion video just to be safe.

Those of you who are up to date on your baseball research may been keen to point out that you can in fact make pitches move glove side with a spin direction suggesting arm side run using SSW. However, for 99% of people this is not the case. I'll discuss this more in future articles.


Driveline Edge

“Statcast Search.” Baseballsavant.Com, MLB Advanced Media, baseballsavant.mlb.com/statcast_search.

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