Those new to watching baseball might marvel at the craziness of the pitches thrown. Aside from the sheer velocity – 100 mph heaters look scary! – pitchers make baseballs curve, bend, slide and even flutter. It can make a non-player wonder: What’s the hardest pitch to hit in baseball?

The hardest baseball pitch to hit varies, depending on the hitter’s skills, experience and preferences. However, 2 pitches stand out according to swing-and-miss data, and comments from top hitters: the split-fingered fastball, known as a “splitter,” and the slider.

A look a few years ago at MLB hitters’ “whiff rate” — how often batters swing and miss on pitches — noted the slider registered a 17.5% whiff rate, behind only the splitter’s 19.4%. However, the same study noted that only 16 pitchers tossed what would qualify as splitters, so the slider is probably the most-used “out” pitch in the majors.

But in terms of the hardest pitch to hit, consider a statement by Hall of Famer Tony Gwynn, who many consider among the best hitters ever, for ESPN online: “The splitter was the single most difficult pitch for me to hit during my career.”

Gwynn had 9,288 at bats during his 20-year career — and struck out only 424 times, or just 21.7 strikeouts on average per season. Cracking 100 Ks a season is bad, and too many players today strike out 200 times or more.

What makes the spitter and slider so hard to hit? What about other tough pitches?

Why Hitting Certain Pitches is So Difficult

Let’s explore the reason for use of the word “varies” above. As no pitchers are exactly the same, few hitters resemble each other either, whether in terms of the physical swing, mental capacity in the batter’s box, courage or other measures.

Hitting a hard round object coming at you, thrown at full or near-full effort, with a round wood club is the most-difficult single act in sports. Ask Michael Jordan, all-universe in basketball, a light-hitting minor leaguer in baseball.

That said, some hitters wait for fastballs to feast on, purposely letting curvy or slower tosses pass by. Others learned how to time off-speed pitches and hit them a particular way.

Overall, the best ways to get batters to swing and miss are messing with their timing, and making the ball move after the batter’s brain decides to commence a swing. Think about this: the human eye on average takes from 100 to 400 milliseconds to blink. A baseball thrown 100 mph takes 396 milliseconds from a pitcher’s hand to home plate.

Batters literally have a split second to choose to swing. Therefore, when a ball does something unpredictable mid-flight — like with the splitter, which can make balls drop suddenly right before or even on home plate, or the slider which is thrown at near-full velocity and moves sideways instead of down like a slower curveball — chances are slim for solid contact.

Additionally, batters naturally take note of the speed of a pitcher’s arm to try to gauge how fast the ball will arrive. Well, pitchers in recent decades have perfected the changeup — a deception act where the pitcher’s arm moves as if tossing a fastball, but with a grip that allows the ball to spin and travel more slowly therefore causing batters to swing too early.

Pitchers with great changeups, or those who can adjust the speed of splitters or sliders even if just by a few mph, tend to have great success in the Major Leagues.

More Insight into Baseball’s Toughest Pitches

Then why don’t pitchers just throw the splitter and/or slider 100% of the time? The answer is torque on their physique, namely the elbow and shoulder.

Some say it’s not a natural movement on a human body to throw things as hard as possible overhand, that throwing underhand is more natural and healthy. The tendency for professional pitchers to have arm troubles and major surgeries seems to back it up.

That could be true for just straight fastballs. But throwing sliders is especially hard on elbows because of a twisting action needed at the release point. The same is true for the spitter to a lesser extent, because the hand snaps hard at the release. The result can be like throwing a tennis ball hard too much — the elbow just doesn’t like it.

Plus, throwing difficult pitches can be tiring, and most pro pitchers are keenly aware of the importance of stamina on the mound. Get tired and your pitches might not move like you want them to. Pitching is an exact science, and movement and location are vital. Accident pitches get hit hard in pro baseball.

So pitchers tend to mix up their pitches, to throw fastballs or changeups as often as possible, moving the location around to set up other pitches.

Other factors to consider regarding tough pitches to hit:

• What is a slider, really? It’s gripped like a fastball, but at delivery the pitcher will slightly turn the hand at the release point allowing seams to cause air-flight drag and with it ball movement beginning about halfway to home plate. It’s basically a harder-thrown curveball, with a lateral break instead of a curveball’s downward movement.

• While the splitter may be the hardest pitch to hit, it also can be the most difficult to throw — at least effectively. Not every pitcher can develop the grip and arm action needed to make the ball move at the end of the ball’s flight. The problem with the splitter is, if it does not move, it can get hammered by hitters. Pitchers tend not to throw the splitter unless he knows it seems to be working that day. Not every pitcher has the splitter in his repertoire.

• Not every baseball fan is familiar with the splitter or slider, but most have heard of the curveball since the term is used off the field in American lexicon. Is a curveball hard to hit? For some pitchers, you betcha. For instance, at one point in their careers, former big league aces A.J. Burnett and Roy Halladay enjoyed whiff rates of 48.3% and 39.6% respectively. Expert hurlers might even give nicknames to their curve, like Uncle Charlie, or The Hook.

• Pitching success might depend on confusing a batter, but what about totally perplexing him? Enter the knuckleball, which is thrown unlike any other pitch — and can move in ways unknown even to the pitcher. The knuckler is gripped (mostly) by the fingernails and tossed with a straight-wristed pushing motion so the ball does not spin like normal. The result is an aerodynamic phenomenon that makes the ball float, jump, flutter and/or bounce as air molecules grab at the ball’s seams or anything else they can affect on the ball’s surface.

Is a knuckleball hard to hit? Again, it depends on the hitter. Some batters hate facing knuckleballers (who are relatively rare) because of the ball’s unpredictable movement or very slow velocity; others just crush to softer-tossed balls, a la Aaron Boone to end the 2003 American League Championship Series. Of note is how less stressful it is to throw a knuckleball … Knuckle-centric pitchers can last longer in games and some pitch well into their 40s without serious injury.

Other Factors Contributing to Swings-and-Misses

Aside from success rates for certain batters with specific pitches, game circumstances can play a part, too. True professional hitters will consider the game situation when approaching a turn at bat. This can mean the number of outs in an inning, the game’s score, how late in the game the at bat occurs, runners on base, and where those runners might be.

Sometimes a batter just wants to get on base any way possible, or to move runners or the batting lineup along to the next hitter. For this, they love knuckleball pitchers, who can’t really control where the ball will end up and are often prone to walks.

Other times the situation calls for a batter to simply hit a ground ball behind runners so they can advance, or a fly ball deep enough so runners can tag up. In these instances, batters are more able to wait on certain pitches and work with them to get the desired results. Hitting can be easier when you don’t have to swing as hard to do what you need to do.

Still other times batters might take more pitches than usual, or try to foul off pitches purposely, to run up the count on pitches for a particular hurler, hopefully tiring him out.

A Word on Fastballs

In the higher levels of baseball, even the fastball has variants. Grips and arm actions can differ and make the ball arrive to the batter differently, and location can be huge. For instance, a 4-seam fastball (gripped with the index and ring fingers parallel with the seams) spins through air molecules differently than the 2-seam fastball (gripped with those same fingers along seams).

The difference is how the seams are aligned during spin, sometimes causing “cuts” of the ball at the very end, a la Mariano Rivera’s famous cutter. Not all pitchers get the same cutting action from different fastball grips, but those who do can use it advantageously.

Questions Related to Tough Baseball Pitches

Question: Why is the splitter so bad for arms?

Answer: Any twisting or snapping action on the elbow is not good for most arms, and the splitter requires a solid grip and snap to create the spin that causes the late movement to avoid bats. There are more scientific reasons, but overall most pitchers understand which pitches seem to cause pain, and there have been a few that have noticeably reduced the number of split-finger fastballs they toss.

Q.: Why is it called a “slider”?

A.: Because its movement “slides” side to side, horizontally, as opposed to the vertical or downward action of curveballs. Sliders are thrown harder than curveballs, generally, so they look like fastballs out of a pitcher’s hand before sliding laterally. It’s similarity in appearance to a fastball is a major reason the pitch causes batters fits.

Faster pitching in recent years has made hitting even more difficult. The average fastball has increased at least 1.5 mph, giving batters even less time to choose whether it’s a fastball, slider, splitter or whatever else is hurled at them.

See Also:
Why Is The Pitcher’s Mound Raised?
What is Tipping Pitches in Baseball? (Here’s The Answer)
Can You Pitch Underhand in Baseball?