The Quest for Heat: A History of Chasing the Magic Number

There is perhaps nothing in American sports quite as visceral, or as mythologized, as the fastball. It is the atomic unit of baseball. The confrontation is primitive: a man with a stick standing sixty feet, six inches away from a man with a rock. The man with the rock says, “Here it comes. Try to hit it.”

For over a century, we have been obsessed not just with throwing it past the batter, but with quantifying exactly how fast that rock was traveling. We love the number. We fetishize the triple digits. But have you ever wondered if the 100 mph thunderbolt thrown by Nolan Ryan in 1974 is the same creature as the 100 mph heater thrown by Hunter Greene today? The answer is complicated, buried in a history of ballistics labs, motorcycles, and military-grade radar.

The Dark Ages of “Fast”

Before we had doppler radar or high-speed cameras, speed was a feeling. It was the sound of the ball hitting the catcher’s mitt—a heavy, dry pop that echoed differently than a curveball. Writers used words like “smoke,” “hummer,” and “high hard one” because they didn’t have decimals.

But human curiosity is a nagging thing. We needed to know who was actually the fastest.

In 1912, the primitive desire to measure speed led Walter Johnson, the “Big Train,” to a munitions laboratory in Bridgeport, Connecticut. This wasn’t a baseball facility. It was a place where they tested bullets. Remington Arms engineers set up a woven wire screen and asked Johnson to throw his fastball through it. The time it took the ball to travel from the screen to a steel plate was measured by a chronograph.

The result? 122 feet per second, or roughly 83.2 mph.

Now, before you scoff at that number and assume modern high schoolers throw harder than the Deadball Era legends, consider the context. Johnson was throwing into a small target in a lab, wearing street clothes. Later recalculations suggest that if adjusted for the drag and the point of measurement, Johnson was likely touching the mid-to-upper 90s. He was an anomaly. A freak of nature in an era where guys pitched to contact to save their arms for the 9th inning.

Then came Bob Feller. The “Heater from Van Meter” engaged in perhaps the greatest publicity stunt in pitching history. In 1946, Feller stood on a mound while a speeding police motorcycle drove past him at 86 mph. Feller threw the ball. The ball beat the bike.

Scientific? Hardly. entertaining? Absolutely. It confirmed what every hitter in the American League already knew: you barely saw the ball when Feller let it go.

The Radar Revolution and the “Slow Gun”

The game changed forever in the 1970s. A tool originally designed to catch speeding motorists found its way into the hands of scouts. The radar gun, specifically the JUGS gun, introduced the era of the “gun reading.” But here is where history gets murky, and where your uncle’s arguments about Nolan Ryan throwing 108 mph usually fall apart.

In the early days of radar, guns measured the speed of the ball closer to home plate. We call this the “slow gun.” Friction is a thief; air resistance slows a baseball down by about 8 to 10 mph from the moment it leaves the hand to the moment it crosses the plate.

So, when Nolan Ryan was clocked at 100.9 mph in the ninth inning of a game in 1974, that measurement was taken roughly 10 feet in front of the plate. If you calculate that back to the release point, which is how we measure velocity today with Statcast, Ryan was likely throwing closer to 108 mph.

Today, we use the “fast gun.” Modern measurement happens immediately out of the hand, usually at 50 feet from home plate. This inflation makes modern pitchers look consistently faster, but it also means we have been shortchanging the legends of the past. If Steve Dalkowski, the erratic minor league legend who supposedly threw harder than anyone who ever lived, had pitched in front of a modern TrackMan unit, would the board have lit up with 110? We can only dream.

The Statcast Era: Precision and Velocity Inflation

In 2015, Major League Baseball introduced Statcast, a tracking technology using radar and cameras to capture data on every movement on the field. We no longer guess. We know the spin rate, the vertical break, and the release point to the millimeter.

We are currently living in the golden age of velocity. Training methods have evolved. Pitchers are no longer pacing themselves to throw complete games; they are max-effort machines designed to throw 20 pitches at absolute limit capacity and then go sit in an ice bath.

The average fastball velocity has ticked up relentlessly. A 95 mph fastball, once the territory of closers and aces, is now league average. If you don’t touch 97, are you even trying?

Below is a look at how the average four-seam fastball velocity has hovered during the mature Statcast era.

The Tale of Two Fastballs

Not all heat is created equal. While we obsess over the radar reading, the grip dictates the life of the pitch.

The four-seam fastball is the classic “rising” fastball. By gripping the ball across the horseshoe seams, the pitcher generates backspin. This doesn’t actually make the ball rise (gravity is undefeated) but the backspin fights gravity longer than the batter’s eye expects, creating an illusion of lift. This is the pitch Roger Clemens used to climb the ladder. It is the pitch Justin Verlander uses to challenge hitters at the top of the zone.

The two-seam fastball (often synonymous with the sinker) is a different beast. Gripped along the seams, this pitch has less backspin and more sidespin/topspin influence. It drops hard and runs to the arm side. It is designed to break bats, not miss them. A 98 mph two-seamer that bores in on your hands is perhaps the most unpleasant sensation in professional sports.

The Evolution of “Velocity” Pitches

The obsession with speed has bled into pitches that aren’t supposed to be fast. In the old days, you had a fastball and a “change of pace.” Today, we have the “hard slider” and the cutter.

The Cut Fastball (Cutter) gained prominence with Mariano Rivera. It looks like a four-seamer until the last ten feet, where it takes a sharp, late left turn (for a righty). It travels at 88-94 mph. It is fast enough to look like a heater but moves enough to miss the barrel. It is the reason thousands of maple bats have died a splintered death.

Then there is the Slider. Historically a breaking ball that traveled in the low 80s, the modern slider has morphed. We now see pitchers like Jacob deGrom throwing sliders at 92-95 mph. At that speed, the physics are baffling. It is essentially a fastball that forgot how to fly straight. This evolution has birthed the “Sweeper,” a variation of the slider that prioritizes horizontal movement over vertical drop, becoming the trendy pitch of the 2020s.

The Human Limit

We have to ask ourselves: Have we hit the ceiling?

The ulnar collateral ligament (UCL) is a small band of tissue in the elbow. It was not designed by evolution to withstand the torque required to throw a baseball 105 mph. We are seeing Aroldis Chapman and Jordan Hicks push the boundaries of physics, but the cost is often the durability of the arm.

As we continue to refine the measurement of speed, moving from motorcycles to military radar, the game remains the same. The batter has less than half a second to decide if the white blur coming at him is a four-seamer at the letters or a slider diving for his shoelaces. No machine can measure the courage it takes to stay in the box.

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Frequently Asked Questions

1. What is the fastest pitch ever officially recorded? The fastest pitch officially recorded in the Statcast era (and generally accepted as the modern record) is 105.8 mph by Aroldis Chapman on September 24, 2010. While there are legends of faster pitches from the past, Chapman’s heat is the verified gold standard.

2. Why does a 100 mph pitch look faster from some pitchers than others? This often comes down to “perceived velocity.” Factors like the pitcher’s extension (how far down the mound they release the ball) can make the ball reach the plate sooner. A pitcher with a long stride releases the ball closer to the batter, giving the hitter less reaction time.

3. What is the difference between a sweeper and a slider? A sweeper is a type of slider that is designed to have more horizontal movement (glove-side run) rather than vertical drop. While a traditional slider might break down and away, a sweeper “sweeps” across the zone laterally. It has become very popular in the analytics era because it is effective against opposite-handed hitters.

4. Did Nolan Ryan actually throw 108 mph? It is scientifically plausible. The 100.9 mph reading he recorded in 1974 was measured near the plate. If you apply the physics of drag to calculate the speed out of his hand (the modern standard), the velocity would likely be between 108 and 109 mph. However, without a time machine and a TrackMan unit, it remains a legendary estimation.