Batters see knuckleballs much less frequently than more conventional pitches. Of the thousands of professionals who've pitched in Major League Baseball, only 84 qualify as knuckleball pitchers, according to Knuckleball Headquarters. The rarity of the pitch, also called a floater, may contribute to its effectiveness: The more often a hitter sees a pitch, the better he can adjust his swing.
Most important to the knuckler's evasiveness, however, is the pitch's erratic flight to the plate-an effect achieved because the ball is thrown with little or no rotation. Without rotation, the knuckleball will flutter, dance, and generally behave unpredictably. (The key is to throw the ball with a stiff wrist.)
The science behind the knuckler was clarified when engineers Eric Sawyer and Robert Watts of Tulane University in New Orleans conducted wind tunnel experiments in 1975. They found that pressure would build up on one side of the ball and then the other, causing it to dart back and forth from its original trajectory.
One of the elite 84 knuckleballers, Jim Bouton, who won 21 games as a fastball pitcher for the Yankees in 1963, was able to extend his career as a knuckleballer after an injury robbed him of the fastball. An author as well, Bouton wrote the celebrated Ball Four. An update, Ball Four-The Final Pitch, appeared in 2000.
Bouton learned the pitch as a youngster from instructions on the back of a cereal box. He and his brother then threw hundreds of attempted knucklers in the yard, until he finally launched a genuine spinless pitch that dropped at the last minute, hitting his brother in the knee. "Ow!" the sibling yelled, "what a great pitch!"
"I spent my teenage years maiming my brother and father, and anyone else who tried to catch my knuckler," Bouton remembers. Because he also had a blazing fastball, the teams he pitched for discouraged the knuckleball. "A fastball is like a jackhammer, and a knuckleball is like brain surgery," he says. "I could not have mixed the two very well."
I do not have much knowledge of the intimacy of the game, but this pitch sounds dangerous, particularly, if not in a professional environment. I am surprised that it is still permitted if it is thought to hurt others in the process.