In MLB, what constitutes a balk?

fredsixties

In MLB a balk is genrally defined as any motion by the pitcher that is a deliberate attempt to deceive a baserunner. There are numrous type of balks, the most common being any motion or movement by pitcher (usually the hands) other that either pitching to the batter, or stepping off the rubber, after coming to a set position. Sep 18 09, 8:55 PM

star_gazer

In baseball, a pitcher may commit a number of illegal motions or actions which constitute a balk. A balk ordinarily results in an immediate dead ball and nullification of any pitch, and each runner is awarded one base. The batter generally returns to bat with the previous count. There are cases when a balk may be ignored partially or completely, though this is very rare. The balk rule in Major League Baseball was introduced in 1898. http://en.wikipedia.org/wiki/Balk Sep 18 09, 10:47 PM