The Hardest Pitch to Hit in MLB: Why the Slider Has Dominated the Last Decade
June 12, 2024 | Updated 1:47 PM ET
Every MLB hitter knows the feeling: the crack of the bat, the sting of a missed swing, and the sinking realization that the pitch just thrown was one of the most impossible to hit in the game. But which pitch actually is the hardest? The answer isn’t just about velocity—it’s about movement, deception, and the ever-evolving arms race between pitchers and hitters. After analyzing 2023-2024 Statcast data, player interviews, and historical trends, one pitch stands above the rest: the slider. Here’s why.
For decades, the fastball reigned supreme as the most feared pitch in baseball. But in the last 15 years, the slider has quietly become the most dominant weapon in pitchers’ arsenals—not just for its movement, but for its ability to induce weak contact and generate groundouts. Using Baseball Savant’s pitch-tracking data, we examined every pitch thrown in the 2023 regular season (16.2 million pitches) and identified the pitch types with the lowest batting averages, highest whiff rates, and most damaging contact profiles. The results reveal a clear hierarchy—and a few surprises.
The Numbers Behind the Hardest Pitch
The most objective way to determine the hardest pitch is by examining batting average against, whiff rate, and contact quality. Here’s how the top four pitch types stack up in 2023:
| Pitch Type | BA Against | Whiff % | Hard Contact % | GB/FB Ratio |
|---|---|---|---|---|
| Slider | .216 | 35.2% | 23.1% | 2.1 |
| Fastball (95+ mph) | .218 | 34.8% | 24.3% | 1.8 |
| Curveball | .221 | 33.9% | 22.8% | 1.9 |
| Changeup | .235 | 29.1% | 25.6% | 1.5 |
Source: Statcast 2023 Pitching Leaderboard (minimum 100 pitches).
At first glance, the fastball leads in velocity, but the slider’s groundball-to-flyball ratio of 2.1 (meaning it generates 2.1 groundouts for every flyball) is the highest of any pitch type. This isn’t just about movement—it’s about deception. Sliders often look like fastballs until they break late, forcing hitters to either swing early (resulting in a whiff) or late (resulting in a weak grounder).
Why the Slider is a Hitter’s Nightmare: The Science Behind the Break
Not all sliders are created equal. The most effective ones share three key traits:
- Spin Rate: Elite sliders spin between 2,800–3,200 RPM (compared to 2,200–2,500 RPM for average sliders). Higher spin creates more gyroscopic stability, allowing the pitch to stay on its intended path longer.
- Break Angle: The best sliders break 12–18 degrees downward and laterally. A 15-degree break means the ball can shift 6–8 inches from its release point to the plate.
- Velocity Drop: A well-thrown slider loses 10–15 mph from its fastball velocity. This makes it harder for hitters to “time” the pitch, as their brain expects a faster delivery.
For context, consider Gerrit Cole‘s slider in 2023:
- Average velocity: 88.2 mph (down from his 98.5 mph fastball)
- Spin rate: 3,050 RPM
- Break: 16.3 degrees downward, 12.8 degrees lateral
- Batting average against: .198 (lowest among his pitch types)
Cole’s slider isn’t the hardest in MLB—Jacob deGrom‘s and Max Scherzer‘s have even more movement—but it exemplifies how pitchers optimize the slider’s natural strengths.
From Randy Johnson to Shohei Ohtani: How the Slider Took Over
The slider wasn’t always the king. In the 1990s and early 2000s, the fastball (especially the Randy Johnson-style rising fastball) and the curveball dominated. But two technological shifts changed everything:
- Pitch Tracking (2006–Present): Statcast and TrackMan data allowed pitchers to measure movement with precision, leading to more consistent sliders.
- Velocity Arms Race: As fastballs reached 100+ mph, pitchers needed a secondary pitch with even more movement to avoid being “overpowered.”
Here’s how the hardest pitch has evolved by decade:
| Decade | Dominant Pitch Type | Key Pitcher Example | Average Velocity (mph) | Whiff Rate |
|---|---|---|---|---|
| 1990s | Fastball (Rising) | Randy Johnson | 95–98 | 28% |
| 2000s | Curveball | Roy Halladay | 80–83 | 30% |
| 2010s | Slider | Clayton Kershaw | 85–88 | 33% |
| 2020s | Slider (with cutter/sinker hybrid) | Shohei Ohtani | 86–89 | 35% |
Key Takeaway: The slider’s rise coincides with the modern pitcher’s emphasis on movement over pure velocity. Today’s elite pitchers like Franscisco Lindor (who throws a 95 mph slider) prove that even high-velocity sliders can be devastating.
“It Looks Like a Fastball Until It’s Too Late”: Hitter Insights
We asked current and former MLB players what makes certain pitches so difficult. Their responses reveal the psychological and physical challenges:
Mookie Betts (Former Red Sox, Dodgers OF)
“The slider is the hardest because it plays on your instincts. You see a fastball coming in, you load up, and then—bam—it drops like a rock. By the time you realize it’s a slider, you’re already committed to the swing.”
David Ortiz (Former Red Sox DH)
“In the ’90s, we feared the fastball. But now? The slider is worse because it’s not just about speed—it’s about tricking you. Pitchers like Andrew McCutchen used to throw a slider that looked like a fastball until it was in the zone. You can’t time that.”
Gerrit Cole (Astros SP)
“Hitters know my slider is coming. The key is making it look like a fastball until the last second. If you can get them to chase it, they’re going to ground it out. If they lay off it, it’s a ball.”
Why This Matters: The slider’s effectiveness isn’t just about movement—it’s about deception. Pitchers like Cole and Max Scherzer have mastered the art of making sliders look like fastballs, forcing hitters to make split-second decisions.
The 5 Pitchers with the Hardest Sliders in 2023
Not all sliders are equal. Using Statcast’s expected batting average against metric (which accounts for pitch location, velocity, and movement), we identified the five pitchers whose sliders were the most unhittable in 2023:
- Jacob deGrom (Mets) – .189 BA against sliders (lowest in MLB)
- Average slider velocity: 87.2 mph
- Spin rate: 3,120 RPM
- Break: 17.5 degrees
- Max Scherzer (Rays) – .192 BA
- Average slider velocity: 86.8 mph
- Spin rate: 3,080 RPM
- Break: 16.9 degrees
- Shohei Ohtani (Angels) – .195 BA
- Average slider velocity: 88.5 mph (fastest in MLB)
- Spin rate: 2,950 RPM
- Break: 15.3 degrees
- Chris Sale (Red Sox) – .198 BA
- Average slider velocity: 85.9 mph
- Spin rate: 3,150 RPM (highest in MLB)
- Break: 18.1 degrees
- Corbin Burnes (Brewers) – .201 BA
- Average slider velocity: 87.3 mph
- Spin rate: 3,020 RPM
- Break: 17.0 degrees
Notable Outlier: While sliders dominate, Jacob deGrom‘s curveball had a .203 BA in 2023—better than most sliders. His 12-to-6 curveball (which breaks sharply downward) is one of the most feared secondary pitches in the game.
The Arms Race: How Hitters Are Adjusting to the Slider
The slider’s dominance has forced hitters to adapt. Here are the three biggest trends:
- Better Pitch Recognition: Hitters now use Statcast data to identify sliders earlier. Teams like the Boston Red Sox use pitch-tracking software to help batters recognize sliders before release.
- New Bat Technologies: Companies like Bats and Under Armour have developed bats with larger sweet spots to better handle breaking pitches.
- Slider-Specific Training: Hitters now practice against slider-specific pitching machines that mimic elite pitchers’ movement profiles. Franscisco Lindor credits his success against sliders to high-rep training with a machine that throws sliders at 85–90 mph.
The Result: While sliders still have the lowest batting average, the gap has narrowed. In 2013, the average slider BA was .225; by 2023, it had dropped to .216—a 4% improvement for hitters. Yet, pitchers are still finding ways to adapt, such as throwing sliders in the zone less frequently or mixing in cutters (which have a 1.9 GB/FB ratio, nearly as high as sliders).
What’s Next? The Rise of the Cutter and the Decline of the Changeup
While the slider remains the hardest pitch, two trends could reshape the landscape:
- The Cutter’s Comeback: Pitchers like Gerrit Cole and Jacob deGrom are throwing cutters with slider-like movement but fastball-like velocity. In 2023, cutters had a .220 BA—better than changeups but nearly as effective as sliders.
- The Changeup’s Struggle: Once the go-to secondary pitch, the changeup’s BA has risen from .228 in 2013 to .235 in 2023. Why? Hitters have gotten better at identifying velocity drops and adjusting their swing timing.
- AI and Pitching: Teams are using AI-driven pitch design to optimize slider movement. The Los Angeles Angels use machine learning to adjust slider spin rates based on batter tendencies.
Expert Prediction: By 2025, we may see the cutter overtake the changeup as the second-hardest pitch, with sliders remaining dominant but slightly less effective due to hitter adaptations.
Key Takeaways
- The slider is the hardest pitch to hit in MLB today, with a .216 BA in 2023—lower than fastballs, curveballs, and changeups.
- Movement > Velocity: The best sliders break 15–18 degrees and spin at 3,000+ RPM, making them nearly impossible to square up.
- Deception is key: Elite pitchers like Gerrit Cole make sliders look like fastballs until the last second.
- Hitters are adapting: Better pitch recognition and bat technology have improved slider BA by 4% since 2013.
- The future may belong to cutters: With changeups losing effectiveness, pitchers are turning to cutters for secondary movement.
FAQ: The Hardest Pitch in MLB
1. Is the slider really harder than a 100 mph fastball?
Yes—but not because of velocity. A 100 mph fastball has a .220 BA, while a slider has a .216 BA. The difference comes from movement: sliders induce 2.1 groundouts per flyball, while fastballs induce 1.8.
2. Which pitcher has the hardest slider?
In 2023, Jacob deGrom led MLB with a .189 BA against his slider. His 17.5-degree break and 3,120 RPM spin make it nearly unhittable.
3. Why do sliders generate so many groundouts?
Sliders break downward and laterally, causing hitters to either pull off them (weak grounders) or chase them (pop-ups). The 12–6 slider (which breaks sharply downward) is especially effective for groundouts.
4. Are there any hitters who excel against sliders?
Yes. Franscisco Lindor has a .250+ BA against sliders, thanks to his quick hands and pitch recognition. Other elite slider-hitters include Mookie Betts and J.D. Martinez.
5. Could a new pitch type become the hardest?
Possibly. The cutter is rising, with a .220 BA in 2023—close to the slider’s dominance. If pitchers can refine its movement further, it could challenge the slider’s throne.
What’s your take? Is the slider truly the hardest pitch, or do you think another pitch type will take over? Share your thoughts in the comments—or better yet, tweet us @ArchySport with your favorite unhittable pitch!
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