Knuckleball

"(It's) a curve ball that doesn't give a damn. - Jimmy Cannon

A knuckleball (aka knuckler, flutter pitch, butterfly pitch) is a pitch that is thrown very slowly (55-70 mph) with very little spin. A pitcher that throws a knuckleball is called a knuckleballer. Unlike other pitches, whose trajectories can be predicted from their speed and spin, the knuckleball is completely unpredictable, due to the lack of consensus about what causes it to knuckle; the Bernoulli Effect, the Magnus Effect, or an Elongated Wake. It can actually break in one direction and then turn around and break the other way. This makes it very difficult to hit (DIPS suggests that knuckleballers are the only group of pitchers with a consistent ability to decrease opponents' batting average on balls in play) and to catch (catchers of knuckleball pitchers are routinely charged with enormous numbers of passed balls).

"The way to catch a knuckleball is to wait until the ball stops rolling and then to pick it up. - Bob Uecker

Contrary to its name, most pitchers actually grasp the knuckleball with their fingernails or fingertips, not with their knuckles, though young pitchers may find it easier to throw it with their knuckles. The knuckleballer pushes the ball with his fingers as he releases it, which prevents it from getting much spin or much speed. An ideal knuckleball rotates between two and zero times on its trip to the plate.

The main problem with the knuckleball, aside from the difficulty of mastering it for both pitchers and catchers, is that a poorly thrown one can be very hittable - the equivalent of the proverbial "hanging curve ball" or "batting practice fastball". Its main advantage is that puts very little stress on pitchers' arms, and thus knuckleballers can pitch more often and longer than traditional pitchers. This was taken advantage of in the 1960s when knuckleballers were often used as a relief ace (e.g. Hoyt Wilhelm, Eddie Fisher, Barney Schultz or Wilbur Wood). In the 1970s some managers decided to use knuckleballers as starting pitchers more often than others, resulting in a huge number of decisions for Wood or Phil Niekro in certain seasons. In more recent times, the result has been knuckleballers pitching until well into their 40s, like Hough and Tim Wakefield.

Because it is so difficult to master, many knuckleball pitchers specialize in the knuckleball to the near exclusion of other pitches. John Smoltz was one of the few recent pitchers who threw a knuckleball as part of an ordinary repertoire, and he did so very rarely. Currently, Matt Waldron uses the knuckleball as part of an otherwise regular repertoire, while the last true knuckleballer, who relied almost exclusively on the pitch, was Steven Wright. Before World War II many pitchers would use the knuckleball occasionally, often as a form of change-up, and it was only later that it became an exclusive pitch.

Famous knuckleballers include Tom Candiotti, R.A. Dickey, Charlie Hough, Phil Niekro, Joe Niekro, Tim Wakefield, Hoyt Wilhelm and Early Wynn.

Steve Sparks, Jared Fernandez, Charlie Zink, Charlie Haeger, Eddie Gamboa and Steven Wright are some of the most recent knuckleballers. Among this group, only Sparks and Wright were able to establish themselves as major league pitchers for a significant period.

The pitcher credited with inventing the knuckleball is usually Toad Ramsey, who did it out of necessity because an injury suffered while working as a bricklayer prevented him from bending one of his fingers on his throwing hand (he was lefthanded, something that is very rare among knuckleball pitchers). While the pitch he threw was more of a knuckle-curve than a true knuckleball, he established the fact that such a slow pitch with a strong and unpredictable break could be extremely effective against event the best hitters.

Further Reading

• David Adler: "Here are the best knuckleballers of all time", mlb.com, January 5, 2022. [1]
• Michael Clair: "The story behind the first knuckleball may surprise you: An origin story fitting for such a strange pitch", mlb.com, March 28, 2020. [2]
• David Gendelman: "Unpredictable and unmanly: baseball's fear of the knuckleball", The Guardian, September 23, 2016. [3]
• Matt Monagan: "A trip inside baseball's knuckleball factory", mlb.com, June 13, 2024. [4]
• Paul Newberry (Associated Press): "Baseball without the knuckler would be a real shame", USA Today Sports, October 2, 2017. [5]
• Dan Schlossberg: "Dan’s Dugout: Return of the Knuckleball", Latino Sports, May 12, 2016. [6]