Curveball vs Sinker

Curveball vs. Sinker: Fooling Batters for Over a Century

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Two terms in baseball’s distinct language might most perfectly describe what’s associated with them: curveball vs. sinker. These baseball pitches have been confounding batters for well over 100 years now ~ and new variations seem to surface each year. What are they?

In baseball, a curveball is a pitch that does just that, curves, as it approaches the hitter and home plate. A sinker is a sinkerball or sinking fastball, which starts straight but dips downward at the end, as opposed to the long looping trajectory of a curveball. Both are designed to fool hitters because the balls do not fly straight all the way to the catcher.


The difference between the pitches is twofold. First, it’s how they veer from a straight path:

  • Curveballs start high, and then swiftly break either straight down (a “12-6” curveball), or diagonally through the hitting zone, dropping home plate nears. They are thrown in a “forespin” manner, meaning the pitcher makes it spin from the top-forward. They are purposely thrown at a slower velocity than fastballs.
  • Sinkers are straight for most of their flight, except at the very end when it dips swiftly downward, either just before or right on home plate. Sinkers are thrown like fastballs with a backspin and high velocity, only they are released a bit differently than the fastball to cause the sink.

Next, it’s about how fast they travel. Curveballs are what are called “off-speed” pitches, or tosses a few miles per hour slower than regular fastballs (pitches thrown hard without special spins). Sinkers are considered a type of fastball, hurled at a high velocity, but spun in such a way that they don’t remain straight the entire mid-air path.

Both are designed to fool batters in the never-ending game of cat-and-mouse between pitchers and hitters. Here’s a look at both common pitches in baseball.

With Overhand Pitching Came the Curve

The curveball may be the very first type of pitch in baseball thrown not just for sheer velocity. Up until 1884, Major League Baseball pitchers hurled underhanded, or in the style of tossing horseshoes. With underhand pitching it’s hard to make a baseball do much. Not so with throwing overhand.

Pitchers began to experiment with new arm angles, and grips, and ways to release the ball. The most prominent became snapping the wrist very hard downward at the ball’s release, making the ball spin hard diagonally or on a horizontal axis. This spin made the ball’s seams grab air molecules in a way that forced the ball to lean one way or the other during flight.

Early curveballs must have been a scary sight for batters ~ like they are for young hitters today when they first see them. A lot of simple curveballs leave the pitcher’s hand looking like it will come right for your head. The batter’s instinct is to jump back, away from the plate. Unfortunately, they do so at the same time the ball breaks out over home plate.

More advanced curveballs are designed to entice the batter not to swing, meaning, making it appear at first to be a pitch way out of the strike zone, usually high. Pitchers like Barry Zito with a big, looping 12-6 curveball ~ so named after the face of a clock, as the ball starts at the 12 but drops straight down to the 6 ~ found great success.

Mysterious Evolution for the Sinkerball

The sinking fastball has probably been thrown by Major League pitchers for as long as the curveball. It’s just that pitchers didn’t have a name for their particular pitch that tended to dip or drop at the end. For many years pitchers just considered it a special gift from the heavens if their pitches sunk somehow.

It wasn’t until around the 1950s that pitchers like Curt Simmons of the Philadelphia Phillies became renowned for relying on the simple pitch designed not necessarily to make bats miss, but for bats to not strike the pitch squarely.

Most sinkerball pitchers are what are called “groundball” pitchers, because their sinkers drop at the last second causing bats to strike the top part of the ball, resulting in ground balls.

As with the curveball, there are different ways to throw sinkers. A popular method is to just use a “2-seam” fastball grip, that is, holding the ball with two fingers along 2 seams at their closest point on the ball. Basically, holding the fingers along the seams, not across them. For some pitchers, using this grip instead of the 4-seamer causes late dropping movement.

Other pitchers slightly move their wrist at release, or use more pressure on one finger when gripping the sinker compared with a normal fastball grip. Some pitchers rely on getting more side-spin on their fastball, instead of straight vertical backspin, to create the late ball movement.

How Pitchers Use Curveballs and Sinkers

While the curveball might be a preferred pitch to cause a swing-and-miss, it rarely is a pitcher’s primary pitch. That is, few pitchers throw it most often, because curves can be hard to throw for strikes consistently, and also tend to put more stress on the arm from the hard snapping motion needed to toss it.

The curveball is usually a complimentary pitch off the fastball, to give the pitcher an option to give a batter a different look or speed. For some pitchers, when the curveball is working ~ meaning they have great command of it and can throw it for strikes at will ~ they are nearly unhittable.

However, most pitchers learn that they do not always “have” their best curveball. Cold or dry weather, certain winds, or a pitcher’s stamina or well-being all can play a part in how well they can snap off curves.

Good sinkerball pitchers, however, might totally depend on the pitch for success. Many known sinker pitchers like Roy Halladay or Derek Lowe might throw the pitch exclusively at times. You know a sinker is working when batters throughout the game hit a lot of ground balls to infielders.

They’re hitting that type of fastball ~ just not striking it well.

Related Questions

Question: Is it hard to hit a curveball?

Answer: Yes, most of the time. Good pro hitters learn to either recognize a curve early and let it go (not swing), or to hold back on their swing for a split moment to let the bat barrel lag through the hitting zone to hit the ball the “opposite” way. Few batters swing from the heels and hit curveballs great distances. It takes a lot of experience with hitting to handle curveballs. Some minor leaguers never figure it out, and their careers peter out before making the bigs because they couldn’t hit curves.

Q.: What about hitting sinkerballs?

A.: It’s probably easier to hit a sinker, per se. But the real question is, how well? Sinkers don’t break dramatically like a curveball, and for the most part, appear like fastballs into the hitting zone. It’s just the very late movement down tends to make bats strike the top half of the baseball, causing ground balls. Teams with good sinkerball pitchers tend to learn to employ above-average infielders.

See Also:
Slider vs. Cutter: Here’s the Difference
Top 17 Slowest MLB Pitchers in History
Why do Major League Baseball Games Start at Odd Times?

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