One of the more interesting aspects of following a sport is learning about strange rules that have existed, in some cases, for nearly a century. The anti-spitball rule in baseball is a classic example of an odd regulation that rarely ever factors into a modern game.
During the early years of professional baseball, pitchers developed a unique delivery known as the spitball. The pitch involved the player spitting on the baseball in order to reduce friction during the delivery. The pitch came off the mound with unpredictable movement and was very challenging for batters to track. As the years went by, pitchers would enhance the advantage by using sweat from their brow and other sources of moisture.
The spitball was outlawed by professional baseball in 1920. As outlined in the official Major League Baseball (MLB) rule book, a pitcher cannot lick the hand or wipe the brow prior to a pitch. The rule even forbids pitchers from adjusting their pants before directly handling the ball. If pitchers engage in any of these behaviors, they must wipe their hands on their uniform before gripping the ball again.