If you were brand-spanking new to baseball, you could be forgiven for thinking a thrown ball will travel in a straight line. If you wanted to get all high-school physics class about it, the ball travels in an arc -- straight ahead on the horizontal axis but pulled down by gravity through its vertical axis.
In reality, things are a bit more complicated. A baseball has aerodynamic properties influenced by its speed and direction, and by wind resistance to the surface of the ball. By scuffing the ball to give it a rough surface or wetting it to present a slicker surface, a pitcher can make the ball do all kinds of interesting maneuvers when he throws from the mound. For a batter, trying to predict where the ball will go during its flight can be maddening, and detrimental to one's season batting average. (For a detailed breakdown on how this works, check out this article on the Physics of Baseball.)
Officially, "doctoring" a baseball in this way is forbidden by the rules. But in practice, pitchers skilled in the arts of subterfuge and misdirection can still perform plenty of flight-altering modifications to baseballs during play. Here are a few variations:
- Spitball -- also called a spitter, mud ball, shine ball, and other colorful names. Banned from professional baseball after 1920 (with exceptions for a few pitchers at the time), the spitball relied on saliva, tobacco spit, petroleum jelly or other wet or viscous substances applied over a section of the ball to upset the airflow -- causing the pitched ball to deviate sharply, or "break" in flight.
- Scuff ball -- this worked on the opposite principle of a spitball. Instead of lubing up a side of the baseball, the pitcher would use an abrasive to make part of the ball's surface rougher. The aerodynamic imbalance would, again, alter the ball's handling characteristics in flight.
- Mud ball -- a variation of the spitball, mud balls are what you got when formerly white baseballs were stained earthen brown after soaking in a cocktail of tobacco juice, spit and infield dirt. In addition to their unique aerodynamics, mudballs were very hard to see, and highly dangerous, when thrown.
After such techniques were banned, certain pitchers elevated their application to something of a stealthy art form. Pitchers would hide nail files in their belts, glue sandpaper to their fingertips or apply Vaseline to their pants zippers (presumably the last place an umpire would ever inspect). What might appear to be an innocent groin adjustment could in fact be a pitcher discreetly dabbing lubricant onto his finger.
While such doctoring is against the rules today, you'll still occasionally see a pitcher get caught performing orb surgery (or preparing to), like when Tampa Bay Devil Rays reliever Joel Peralta was ejected from a June 2012 game against the Washington Nationals. Officials booted Peralta after they found "a significant amount of pine tar" in his glove [source: Mercury News].
Some have stepped forward in defense of doctored balls. Elwin Charles Roe, aka "Preacher" Roe, a former star pitcher for the Brooklyn Dodgers, outed himself as a spitball thrower in 1955, after his retirement. Over the years, he insisted that the pitch was ethical and not inherently unsafe [source: Goldstein].
Despite appeals to legalize the spitball from people like Preacher Roe, who died in 2008, Major League Baseball continues to ban the practice of ball altering. Considering the gross-out potential, this perhaps isn't a bad idea. How scarred for life would you be as a fan if you caught a home run ball that had been marinating in Vaseline, loogie juice, tobacco spit or any combination of such goop?