Banner by Korrina Gidwani

Spinning Out of Control

By David Scott

Major League Baseball is one of the most analytically driven sports in the world. Every aspect of every player’s game has a statistic attached to it. From launch angle to release point, baseball is becoming increasingly statistics-driven each season, with each MLB team’s analytics department nearly doubling since the beginning of the century. This trend is especially apparent in pitchers who strive for perfection in their game. The motive behind this trend is spin rate. Pitchers use every resource possible to get a leg up, and some will cross the line to do so.

Ever since the 2015 implementation of Statcast, a system of high-tech cameras in every MLB ballpark, major league teams have had access to a plethora of new and advanced metrics. In the years since this statistical revolution, the emphasis on spin rate has increased exponentially. As per the MLB, “A pitcher’s spin rate represents the rate of spin on a baseball after it is released. It is measured in revolutions per minute.” The spin on a pitch is the key to its movement. A pitch traveling 95 mph with a high spin rate will move across the plate much more than a pitch of the same speed with a lower spin rate.

New York Yankees #19 prospect Ron Marinaccio, who is on track to make his MLB debut this year, provided some insight into his experience with spin rate and its significance in the league. “The Yankees, in particular, are super analytical among all the teams in baseball,” Marinaccio says. “I think I am under a little bit more of a microscope.”

Marinaccio throws three different pitches: a fastball, a changeup, and a slider. A fastball is mainly about speed, but a slider focuses on horizontal movement across the plate, as does the slower changeup. That movement is essential to fool batters into swinging and missing.

Marinaccio emphasizes the importance of movement on his pitches. “It’s a little bit of being able to show that you can throw it for a strike, first off, just because when you’re throwing these pitches trying to get a swing and a miss, you don’t want it to be in the best area to hit,” he explains. “Secondly, and probably just as important or more important, is trying to create as much movement on the ball as you can.”

There are a lot of different factors that go into a pitcher creating movement on their pitches. Release point is one of the main factors. “How low or how high you release a ball plays a bunch on your fastball,” Marinaccio says. Release point does not directly affect spin rate, but instead compliments it. Every 100 rpm on a fastball generally translates to about 0.43 inches of movement on the ball, which is a lot considering a hitter only has a two-and-a-half-inch wide bat for contact. Properly aligning release with rise can create a deadly pitch. “A 14-inch vertical fastball from somebody with a low release height is gonna play a lot better than a 16- or 17-inch vertical fastball with somebody that’s got a higher release height, so that’s something that is super deceptive to hitters,” Marinaccio explains.

A pitcher’s grip is also an important tool in their arsenal. The way a pitcher aligns the seams of a baseball with their fingers changes how air travels around the ball and generates spin. Marinaccio explains that he pays attention to the pressure of his grip. “It’s a bunch about pressure, definitely, wherever you’re applying pressure on your fingers.” The way Marinaccio grips his slider is to throw a variation called a seam shifted wake. He explains it as, “The ball is spinning in a certain direction and the flat part, or the smoother part, of the ball spins and creates a wake behind it.”

This pitch utilizes something called the Magnus Effect. To understand how the Magnus Effect works on a pitch, you must also understand the underlying physics. A baseball undergoes three forces once it is released from a pitcher’s hand: gravity, drag, and lift. According to a 2021 study from Physics Today, these forces play into the Magnus Effect’s influence on a baseball. “As a pitched baseball streaks toward the plate, air molecules slam into the ball’s leading face, and a boundary layer of air that is moving slowly relative to the ball wraps partly around the ball. The ball’s spin determines where that boundary layer separates from the trailing face of the ball.” The Magnus Force works in the direction of spin rate multiplied by velocity. The resulting movement on the baseball is opposite the direction of the Magnus Force. To take this into account, when a pitcher wants to throw a slider that breaks to the left side of the plate, he needs to get the ball spinning to the right.

The combined efforts of the Magnus Effect and a pitcher’s skill creates an effective offense to attack a hitter. A low release pitch with the fingers gripping perpendicular to the seams and backspin applied creates a 4-seam fastball. A high release pitch with the fingers gripping parallel to the seams and front spin applied creates a curveball. A similar grip to a curveball but with backspin will create a 2-seam fastball. The combined efforts of a pitcher’s input and the physics of the air around the ball creates an ensemble powerful enough to get a swing and a miss from even the best batters.

There is another way to tap into the power of spin rate, and that is to incorporate an x-factor into the ensemble. The pitcher has their grip, their release, and their spin to effectively attack a hitter with movement, but what if the pitcher could give one of these factors a power up? Extra grip would allow a pitcher to elongate the moment the ball spins off their fingertips to generate a huge burst of spin rate. By drastically increasing the spin rate in the Magnus Effect, a pitcher could theoretically gain inches of horizontal movement on their pitches.

The 2021 MLB season saw this theory become reality. From the get-go, there was something different about this season. The MLB has been continually trending toward a lower batting average, meaning players are getting fewer and fewer hits. From 2000 to 2019 the league batting average dropped from .270 to .252 (2020 excluded due to COVID). At the end of June 2021, the league batting average stood at a measly .239, on pace to be the lowest since 1968. Also, pitchers who had never been strong in their careers were suddenly finding success. In the first half of the season there were a record breaking six no-hitters. Videos of pitchers acting suspiciously on the mound began to surface at the same time. Analysts noticed some pitchers were not only gaining some spin rate, but rather hundreds of rpms, which could give them over an inch or more of additional movement on their pitches. The crisis of spin rate was approaching its climax.

“I think spin rate is one of the toughest things to directly increase,” Ron Marinaccio explains. A jump of multiple hundreds of rpms is just something that cannot be naturally attained in one season. “Sticky Stuff” was eventually pinned as the culprit for this crisis. Pitchers were utilizing various types of adhesive substances such as pine tar and Spider Tack, an adhesive used for powerlifting atlas stones, to better grip the ball. The MLB took notice of this and implemented checks every inning to be sure no pitcher could possibly be using a foreign substance on the mound. After this crackdown, notable pitchers such as Trevor Bauer of the Los Angeles Dodgers and Gerrit Cole of the New York Yankees saw a drop of 243 rpm and 175 rpm, respectively. By the end of the season, the league batting average rebounded back to .244 and the crisis was put to rest.

Spin rate will forever be a part of baseball; there is no leaving it behind. Despite the problems it may cause when pushed too far, it is a valuable asset for pitchers to properly evaluate their skills and work to improve their game. As long as pitchers can continue to utilize their natural abilities rather than outside forces, it will be the batters who will have to change their strategy to accommodate the quickly-improving pitchers. Baseball is an ever-evolving sport, and there will come a time when a new statistic has the league by its throat. For now, spin rate has settled in as the hottest commodity on the market.