Introduction

Jacob deGrom has carved out a place among the most dominant pitchers in Major League Baseball history, earning two Cy Young Awards and posting some of the best statistical seasons of the modern era. His career arc, however, has not been a straight line of effortless success. Pitchers at the highest level face a constant arms race: batters study video, adjust their approaches, and force pitchers to evolve or become obsolete. deGrom’s ability to recognize those adjustments and systematically retool his arsenal has been the defining characteristic of his sustained excellence. This article examines how deGrom adapted his pitching style over the years—moving from a power-first approach to a more nuanced, multi-pitch operation—and why those changes have kept him elite even as the league’s hitters grew increasingly sophisticated.

Early Dominance: The Fastball–Slider Foundation

When deGrom first broke into the majors in 2014, his core arsenal was deceptively simple: a four-seam fastball that sat in the mid-90s and occasionally touched 100 mph, paired with a slider that he could throw to both right-handed and left-handed batters. The fastball had elite carry and induced weak contact high in the zone. The slider, thrown with sharp vertical drop, gave hitters a second look that made them uncomfortable. In his early seasons, batters struggled to consistently square up either pitch. According to FanGraphs, deGrom’s strikeout rate climbed steadily from 7.8 K/9 in his rookie year to over 10 K/9 by 2017. The fastball–slider combination accounted for more than 80 percent of his pitches during that period.

Why the Two-Pitch Mix Worked

The key to deGrom’s early success was the velocity differential and movement contrast between the two pitches. His fastball came out of a low three-quarter arm slot that created natural deception. When he threw the slider, it tunneled with the fastball for the first 20–25 feet before breaking down and away. Hitters could not differentiate the two pitches early in the flight, so they often committed to the fastball before realizing the slider was coming. This “tunneling effect” made his slider almost unhittable. In 2015, opponents hit just .194 against deGrom’s slider, with a whiff rate over 45 percent. The fastball’s vertical approach angle was consistently steep, forcing batters to square the ball on the barrel’s sweet spot or miss entirely.

The 2014–2017 Statistical Snapshot

During this foundational period, deGrom posted a 2.98 ERA across 111 starts, with a 1.15 WHIP. His fastball averaged 94.6 mph but regularly spiked to 97 in key moments. The slider generated a 20.1 percent swinging-strike rate, well above the league average for that pitch type. What made the two-pitch mix sustainable early on was deGrom’s ability to locate both pitches to all quadrants of the strike zone. He could elevate the fastball to get whiffs, then bury the slider low and arm-side to freeze right-handed batters. Lefties, however, gave him more trouble: they slashed .261/.318/.410 against him in 2015, suggesting that a changeup would eventually be necessary.

The League Catches Up: Batters Adjust

By 2018, the baseball analytics revolution had spread through every clubhouse. Teams began feeding batters detailed spray charts, pitch-identification algorithms, and Biomechanics reports. Opponents noticed two vulnerabilities in deGrom’s approach: he was predictable in fastball counts, and his slider had a distinct spin signature. Hitters started sitting on the fastball—especially first-pitch fastballs—and laying off sliders that lacked command. In 2019, deGrom’s slider whiff rate dropped below 40 percent for the first time in three years. Batters also began to spread the strike zone, forcing him to throw more pitches in the heart of the plate. This strategic shift was captured by Statcast data: deGrom’s zone rate on first-pitch fastballs climbed above 55 percent, and hitters’ contact quality spiked accordingly.

The Shift in Approach

deGrom himself acknowledged the arms race in interviews. “They know what you throw now, they know the sequences,” he told reporters. “I have to stay ahead of them, or I’ll get punished.” The result was a noticeable uptick in hard contact against his fastball. In 2019, batters posted a .404 slugging percentage against deGrom’s four-seamer—the highest of his career to that point. The free-swinging era of the two-pitch pitcher was over; deGrom needed to add layers to his game. He also began to see more “take” swings on his slider, as hitters learned to spit on the pitch when it started outside the zone. This forced deGrom to throw more strikes with the slider, which in turn made it more hittable.

The 2018–2019 Statistical Turning Point

Despite the league’s adjustment, deGrom still won the 2018 Cy Young Award with a 1.70 ERA and 269 strikeouts. But underlying metrics showed cracks: his .296 BABIP was the highest of his career to that point, and his strand rate (82.4 percent) was unsustainably high. By 2019, his ERA rose to 2.43, and his FIP jumped to 2.73. The chase rate on pitches outside the zone fell from 38 percent in 2017 to 31 percent in 2019, indicating that batters were no longer expanding the zone against him. Something had to change.

DeGrom’s Adaptation Arsenal

Starting in 2020 and accelerating through 2021, deGrom overhauled his pitch mix in several distinct ways. The changes were not random but carefully orchestrated to counter specific hitter tendencies revealed by the data. He worked closely with the Mets’ pitching coach Jeremy Hefner and independent pitch-design labs to refine each new offering. The adaptation was methodical, almost surgical.

Increased Use of Off‑Speed Pitches: The Changeup and Curveball

The most obvious change was the increased reliance on his changeup and curveball. In 2018, deGrom threw a changeup only about 5 percent of the time. By 2021, that number had jumped to nearly 14 percent. The changeup was not new—he had thrown it sporadically—but he began using it as a primary weapon against left-handed batters. Unlike many changeups that fade arm-side, deGrom’s changeup had late sink and tumble, making it an excellent complement to his high-spin fastball. The added usage kept lefties from diving on fastballs middle‑in. By 2021, left-handed batters hit just .143 against deGrom, a dramatic improvement from the .237 they posted in 2019.

The curveball also saw a resurgence. In 2020, deGrom threw the curveball 8.5 percent of the time, up from around 4 percent in previous seasons. The curveball gave him a pitch with a completely different velocity band (low-80s) and a 12‑to‑6 break that froze hitters expecting the slider’s two‑plane movement. The three‑pitch progression—fastball, slider, curve—allowed deGrom to throw any pitch type in any count, breaking the hitter’s pattern recognition. His curveball whiff rate jumped to 35 percent, and opponents slugged only .210 against it in 2020.

Varying Pitch Speeds: Creating Chaos

deGrom also became more aggressive in mixing speeds within the same pitch type. He learned to manipulate his fastball: throwing a four‑seamer at 98 mph, then a two‑seamer at 94 mph with run, then back to the four‑seamer at 100 mph. The change in velocity—especially the soft fastball—disrupted timing. Batters who geared up for 98 mph were late on the 94 mph pitch, while those who tried to slow down often jumped on the 100 mph fastball. Speed variation became one of deGrom’s most underrated tools. According to Baseball Savant, his fastball velocity range expanded by nearly 5 mph between 2018 and 2021, from a standard deviation of 1.2 mph to over 2.5 mph within a single start. He also began throwing an occasional sinker—a pitch he had used only sparingly earlier—to induce ground balls when needed.

Changing Release Points: Deception by Small Degrees

While deGrom’s mechanics have always been clean, he occasionally altered his arm angle and release point within starts. Video analysis shows that early in his career he released the ball from a consistent slot near 1:30 on the clock face. Later, he began experimenting with a slightly lower slot on his changeup and a higher slot on his curveball. The changes were subtle—maybe two or three inches—but enough to change the perceived plane of the pitch. Hitters who learned to pick up the ball from one angle were suddenly thrown off. The constant tweaking made it nearly impossible to sit on a pitch based on arm slot. In 2021, Statcast’s release point variability metric showed deGrom in the 98th percentile among starters, meaning his release point fluctuated the most while still maintaining pinpoint command.

Strategic Pitch Sequencing: The “Reverse Engineer” Approach

Perhaps the most intellectual part of deGrom’s adaptation was his sequencing strategy. Early in his career, he often followed a hard‑fastball‑then‑breaking‑ball pattern, especially ahead in the count. As batters caught on, he started to “reverse engineer” sequences: throwing a first‑pitch breaking ball, then following with a fastball, or using a changeup in a 2‑0 count. The goal was to prevent hitters from establishing any pattern. He also began to expand the zone with two strikes, using his curveball or changeup low and away to induce chases. In 2020, deGrom posted an unprecedented 14.3 K/9, largely because batters could not guess what was coming next. The sequencing change was data-driven: deGrom studied which counts opponents were most comfortable with and then attacked those counts with his least-expected pitch.

The 2020–2021 Statistical Peak

Over that two-season span, deGrom made 38 starts and compiled a 1.62 ERA with 447 strikeouts in 244 innings. He allowed just 15 home runs, a rate of 0.55 per nine innings—the best in baseball. His walk rate remained elite at 5.7 percent despite the expanded repertoire. The adaptation had worked beyond expectations. His fastball usage slipped below 50 percent for the first time in 2021, as he leaned more heavily on his secondary pitches. The slider remained his primary strikeout pitch, but now hitters had to account for the curveball and changeup as well, making the slider even more effective.

The Role of Health and Mechanics

Adapting a pitching style requires a resilient body, and deGrom’s history with injuries is well‑documented. After missing time in 2021 with forearm and shoulder issues, he made subtle mechanical adjustments to reduce torque on his elbow. He shortened his stride length slightly and altered his trunk rotation to keep his arm in a healthier slot. These changes did not compromise his velocity—he still averaged 98.8 mph on his fastball in 2022 when healthy—but they gave him more stamina late in games. The mechanics changes also improved his ability to repeat his delivery with each pitch type, a critical factor for maintaining deception.

deGrom also invested heavily in prehab and recovery strategies. He adopted a more rigorous warm-up routine that included weighted-ball exercises tailored to his new repertoire. He worked with biomechanics specialists to ensure that the added changeup and curveball usage did not put undue stress on his forearm. The result was a pitcher who, even after returning from injury in 2023, could still touch 100 mph while throwing his changeup with the same deception as before. The mechanical tweaks allowed him to sustain his adaptation without breaking down completely, though durability remains a concern.

Data‑Driven Adjustments: The Rise of Pitch Design

Modern baseball has embraced pitch design and data analysis, and deGrom has fully invested in the process. He works with the New York Mets’ analytics department and external consultants to review his spin rates, release points, and pitch movement plots. When batters began identifying his slider by spin axis, deGrom altered his seam‑shifted wake by varying his grip. He also started throwing a cutter‑style fastball—a harder slider, really—that blended the movement of his slider with the velocity of a fastball. The cutter gave him a sixth pitch option, though he uses it sparingly. The key insight is that deGrom treats his arsenal as a system of trade‑offs: he is willing to sacrifice a small amount of “stuff” for greater unpredictability.

In 2020, deGrom began working with the Driveline Baseball training facility to analyze his pitch tunneling. They discovered that his slider and fastball shared the same initial flight path for the first 15 feet, but the slider’s spin axis was slightly different, causing some hitters to read it early. By adjusting his grip to align the seams more closely, deGrom made the two pitches almost visually identical. His whiff rate on the slider bounced back above 45 percent in 2021. This level of detail—down to the angle of the seams—separates deGrom from most peers. He is not just a thrower; he is a pitch designer.

“Data tells me what the hitter is expecting. Then I go out there and do the opposite.” — Jacob deGrom (paraphrased from multiple interviews)

The data-driven approach also extended to game planning. deGrom and the Mets’ coaching staff would create specific pitch-sequencing maps for each opponent, based on the previous 100 batted-ball events against him. They targeted hitter weaknesses uncovered by Statcast, such as a tendency to swing at high fastballs or to freeze on low changeups. The result was a game-day plan that changed start to start, not just season to season. This level of customization made deGrom nearly impossible to game plan against, because the plan itself was always shifting.

Impact on Performance and Legacy

The results of deGrom’s adaptations are reflected in the numbers. From 2018 to 2021, he led all starting pitchers in ERA (1.94), FIP (2.05), and strikeout rate (13.7 K/9) while allowing a batting average of just .185. Even in 2023, after returning from injury, his strikeout rate remained elite at 11.8 K/9, and his WHIP was under 1.00. The adaptation story is not just about maintaining dominance; it is about redefining the ceiling of what a pitcher can achieve. deGrom’s ability to evolve made him virtually unhittable for a three‑year stretch—a run that rivals any in baseball history.

Comparison to Other Elite Pitchers

Pitchers like Clayton Kershaw, Max Scherzer, and Justin Verlander also successfully adapted as they aged. Kershaw added a slider and changed his fastball usage. Scherzer learned a curveball and refined his changeup. But deGrom’s adaptation was unique because he dramatically expanded his repertoire while maintaining peak velocity. Most pitchers slow down over time and rely on guile; deGrom added guile while still throwing 100 mph. That combination has made him a prototype for future aces—a model of how to blend power with surgical precision. Verlander, for example, increased his slider usage later in his career but never added the depth of off-speed variety that deGrom did. Kershaw’s velocity declined from 94 mph to 91 mph as he adapted; deGrom’s did not drop at all.

The legacy is already secure: deGrom will be remembered as one of the most dominant pitchers ever, but also as one of the smartest. His adaptation strategy—based on data, physical adjustments, and fearless experimentation—has become a blueprint for modern pitching development. Young pitchers are now taught to think like deGrom: to see their arsenal as a system to be optimized, not a collection of inherited tools.

What’s Next for Jacob deGrom?

As deGrom enters his mid‑30s, the challenge of adaptation will only intensify. Batters will continue to study his tendencies; analytics will grow sharper. To stay ahead, deGrom will likely need to further diversify his sequencing and perhaps adopt a sweeper or split‑finger pitch. The sweeper, a horizontal-breaking slider that has become popular in recent years, could give deGrom a weapon that moves away from right-handed batters in a different plane. He has already dabbled with a splitter in spring training, showing promise as a ground-ball pitch against lefties. Given his willingness to experiment—and his track record of making adjustments work—there is little reason to doubt he can remain elite for a few more seasons, provided he stays healthy.

The broader lesson for baseball is clear: pitchers who treat their craft as a work in progress, who are not afraid to abandon old habits and embrace new data, are the ones who survive the hitter’s adjustments. Jacob deGrom has embodied that philosophy, and his legacy as one of the great adapters is secure. As the game evolves, deGrom’s career will stand as a case study in how to blend raw talent with continuous learning—a masterclass in pitching adaptation.