TIME OF PITCH

Rule 5.07(a):

The time of pitch is defined as the moment the pitcher’s movements commit the pitcher to deliver the ball to the batter.
• In a windup position, this is defined as the moment the pitcher begins the natural movement associated with the pitcher’s delivery of the ball to the batter (i.e., the start of his windup or delivery).
• From a set position, this is defined as the moment the pitcher begins the natural movement associated with the pitcher’s delivery of the ball after the pitcher has come set with both hands together in front of his body.

A runner who advances while the pitcher is in contact with the rubber is considered to occupy the base last touched at the time the pitcher initiates his actual pitching motion to the batter. The pitching motion is defined as any movement that commits the pitcher to deliver the ball to the batter.

So long as the pitcher is not committed to pitch, a runner may advance and is considered to occupy the last base touched at the time the pitcher initiates his actual delivery to the batter.

The preliminary motion known as the “stretch” is not considered the start of
the pitching motion.