I Have Seen the Fastball of the Future, and It Is a Cutter

If you watch a random pitch from a serious league recreation, there’s a greater than even probability you’re going to finish up selecting out a fastball. The fastball is the core idea upon which pitching is known, the theme upon which all variations, from changeup to knuckle-curve, are composed. Our society has three nice institutions: “establish the fastball” in baseball; “establish the run” in soccer; and the Establishment Clause of the First Amendment.

They are all, to some extent, going out of fashion.

The factor concerning the fastball is that it’s as hittable as it’s elementary. Few pitchers can simply pump gasoline previous main league hitters; the rationale a pitcher should set up the fastball is so he can set a hitter’s expectations, then confound these expectations with one thing else. But rather less than a decade in the past, a couple of pitchers discovered that typical knowledge had a blind spot. Pitchers with an distinctive secondary pitch ought to only throw it on a regular basis. This method was pioneered by Rich Hill and some others and reached its zenith in Game 7 of the 2017 ALCS. Lance McCullers Jr., architect of one of many sourest curveballs ever devised, threw 24 of them in a row in a four-inning reduction look with a visit to the World Series on the road.

To hell with the fastball, then. Not for everybody, after all. The pendulum of stylish pitching principle swings backwards and forwards, and loads of pitchers have at all times been higher off mixing several types of fastball than committing full-time to the breaking ball way of life. But on the combination, fastball utilization is on a downward pattern throughout the league, and has been since Statcast was launched.

But when you’re speaking concerning the fastball, it’s a must to be particular, as a result of they arrive in three broad flavors. There’s the four-seamer: excessive velocity, some arm-side run, so little vertical drop we generally speak about it having “rise.” The two-seamer, or sinker: reasonable velocity, excessive arm-side motion, and a few sink. And then there’s the cutter: decrease velocity and glove-side motion, to the purpose that the road between a cutter and a slider could be blurred.

Below is the common motion for every sort of pitch by 12 months since 2015 — four-seamers in blue, sinkers in yellow, cutters in pink:

Since 2015, all the pieces has gotten tougher. In life, usually, sure, however particularly: fastballs are thrown tougher now. The common four-seamer in 2023 is 1.0 mph quicker than it was in 2015; sinkers are up 1.2 mph, and cutters are up 0.7 mph. Sinkers have extra motion than ever in each instructions and are tougher now than four-seamers have been in 2015.

And but the two-seamer has fallen out of favor. The decline of the fastball just isn’t shared evenly among the many three sorts:

No, wait, come again! The scaling on that graph makes the impact look much less pronounced than it’s. In 2015, sinkers accounted for 21.3% of all pitches. This 12 months, that’s down to fifteen.1%, a drop of simply over six proportion factors however virtually 30% by way of complete pitches. As a proportion of the 700,000-plus complete pitches thrown in a typical MLB season, we’re speaking between 30,000–40,000 fewer sinkers than we noticed lower than a decade in the past.

Much of that drop might be attributable to the narrative that developed through the swing aircraft revolution of the late 2010s. The downward motion on a sinking fastball — beforehand regarded as fascinating, because the ball would drop underneath hitters’ bats and result in floor balls — now served to fulfill an uppercut swing flush, resulting in onerous contact and residential runs. But as that revolution has cooled, or on the very least is now not one of many sport’s dominant speaking factors, two-seamer utilization has merely plateaued, not rebounded.

Cutters, the least frequent fastball, are on the rise. A pitch that acquired used within the high-5% vary within the mid-2010s now accounts for 7.8% of complete pitches in 2023. Near as I can inform, there is no such thing as a actual cutter revolution sweeping the nation. Corbin Burnes’ transformation is a couple of years previous at this level; maybe he’s the torchbearer for a complete new technology of pitchers, the third stage on the Mariano Rivera–Kenley Jansen rocket.

Of the highest 100 pitches on Baseball Savant’s run worth checklist, solely 4 are cutters. Adjusting to run worth per 100 pitches, the checklist will get just a little extra closely populated: there are 9 cutters within the prime 100 in RV/100 (minimal 25 PA), however three of these 9 are between 90–99 on the checklist, so perhaps that is an arbitrary endpoints factor.

Acknowledging that some cutters are fastballs and a few cutters are mainly sliders, it’s onerous to attract conclusions primarily based on league-wide information, however right here’s an ironic twist. You’d assume that there can be a cause-and-effect relationship between the rise in cutter utilization and hitters’ success price in opposition to the pitch. In different phrases, it could make sense to throw extra cutters if this have been an unexploited market effectivity. In truth, hitters are getting higher in opposition to cutters — so much higher. The league-wide wOBA in opposition to the opposite two forms of fastball has stayed in a ten–15-point vary over the previous decade. Against cutters, hitters posted wOBAs between .304–.312 from 2015 to 2018. That went up into the mid-.320s by the flip of the last decade. This 12 months, it’s as much as .336.

This season, the league is hitting .267/.332/.445 off the cutter; these slash marks are inside a couple of factors of what Wander Franco and Manny Machado are hitting this 12 months. Would you line as much as flip opponents into Manny Machado and Wander Franco? I feel not.

Another approach of framing that info is that this: Opponents are slugging virtually 40 factors higher in opposition to cutters than they have been within the mid-2010s. This is the worst season for cutters within the Statcast period. And regardless of all that, a .336 opponent wOBA can be the stingiest season of the Statcast period for both four-seamers or sinkers.

Is the cutter a more practical pitch now than it was eight years in the past? On a league-wide foundation, no. But even at its low-water mark, it’s more practical than different fastballs, which by Hill’s Law means it needs to be thrown extra and different fastballs thrown much less. Which is precisely what’s taking place:

So what makes the cutter so particular? It’s the one fastball with glove-side motion. It’s the fastball, in different phrases, that doesn’t transfer like a fastball. The orthodox place on lateral motion is that transferring the ball away from the batter makes it tougher for the batter to hit. But after I broke out cutter utilization by platoon benefit, I couldn’t discover an impact to clarify the league-wide uptick. Left-on-left cutter utilization has risen and fallen; right-on-right cutter utilization has gone up since 2015, however right-on-left cutter utilization has gone up extra. The thesis that elevated cutter utilization is a brand new option to acquire the platoon benefit on fastballs doesn’t maintain up.

I additionally observed that the downward pattern in fastball utilization, which is even higher whenever you take cutters out of the equation, was not matched by a rise in changeups and splitters, which even have arm-side motion. In truth, we’re seeing fairly a big uptick within the proportion of pitches which have glove-side motion, however the proportion of pitches which have batter-side motion has fluctuated inside a hall of simply 1.5 proportion factors all through the Statcast period. The proportion of pitches thrown the place the pitcher has the platoon benefit has additionally gone up and down inside a window of 1.5 proportion factors, and that’s accounting for the introduction of the three-batter minimal in 2020.

All of this results in an interesting pattern concerning the platoon benefit. This season, pitchers with the platoon benefit are throwing pitches with batter-side motion (abbreviated to BSM beneath, within the curiosity of becoming all the pieces into the chart) simply 58.0% of the time. That’s the bottom mark of the Statcast period, down from 64.6% in 2015 and 66.3% within the high-water mark of 2017. And that is sensible. If the purpose of the platoon benefit for a pitcher is to play keep-away with the breaking ball, pitchers are doing that greater than ever. It’d be cheap to count on that quantity to drop in years to return.

But that’s not the fascinating half. The fascinating half is that when pitchers don’t have the platoon benefit, they’re throwing extra pitches with batter-side motion than ever — much more:

Same-handed hitters? You’re going to get much more breaking balls. Opposite-handed hitters? You’re going to get much more breaking balls, too. “Throw your best stuff more often” defies the standard understanding of the fastball’s function in pitching. Apparently it defies the standard understanding of the platoon benefit as properly.