The pitcher may step and throw to an occupied base for the purpose of picking off a base runner or to put out an advancing runner. He must step ahead of his throw in the direction of the base and his step must gain distance in the direction of the base. A jump step is legal but only if the stride foot gains some distance in the direction of the base. The step to the base must precede the throw even if only by a split-second.
When attempting a pickoff throw to an occupied base the pitcher does not have to come to a stop. He may make a pickoff throw at any time throughout the process of his stretch to set position.
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