About 75% of the pitches R.A. Dickey threw at Yankees batters last night hovered around 76 miles per hour. You'd think the Yankee sluggers would feast on such fare, but the Mets right-hander struck out 6 and limited the Yanks to four hits and one anemic run over six innings in the Mets' 2-1 win. Dickey's secret: his knuckleball.
Hitters are irritated by the knuckleball, and so are many catchers who have to corral it. A knuckler floats and dives and swings left or right unpredictably--even the pitcher who throws it isn't sure exactly what it will do.
But how do you throw it, and how does it work?
The mechanics of the pitch aren't drastically different from other pitches except in the grip and the release. A pitcher holds the baseball for a knuckleball pitch like he's preparing to scrape his fingers down a blackboard. The ball is wedged into his hand by the fingertips on top, the meat of the thumb below, and the inside of the pinky on one side.
A pitcher releases a knuckleball like he is flicking water at someone, with the wrist bent at a 90-degree angle, the fingers pushing the ball forward in such a way as to create little or no spin. It's the backspin on a fastball that helps keep it straight as it travels to the plate. For correct form, a pitcher should end his motion in a certain posture, but this is less important to the question of how the knuckleball does what it does.
So what are the physics behind a knuckleball? Crazily enough, it rests on the stitching on the baseball. The small degree to which the stitching makes the ball's surface uneven might seem incapable of making a pitch dance and drop on the way to the plate, but consider that though the stitching is little more than a millimeter thick, there are 108 of those double stitches on a standard baseball.
With a fastball, when it's thrown with a flick of the wrist, a good amount of backspin is put on it, creating a fairly uniform drag behind the ball as it travels. When the ball isn't rotating much at all as it travels through the air, the stitching creates uneven pockets of drag behind the ball, and those pockets tend to grow and collapse as it goes. When the drag changes, the ball's path changes. The result is the knuckleball's dance.
In a Feb. 26 interview with MLB.com, Dickey talked about who has better luck hitting his knuckler. He mentioned the Marlins' Omar Infante as one. And in the process, he offered a good explanation of why he managed to stymie the Yankees last night. The guys that I enjoy facing are most of the bigger hitters--the guys that have a lot of power, said Dickey. They usually try to do more than they can do with the pitch, and so I usually end up having some success with it.