Rule sets / OBR / Quick-Pitch Balk
Quick-Pitch Balk
A pitcher may not deliver a pitch before the batter is reasonably set in the box. Doing so is a balk.
A QUICK RETURN pitch is one made with obvious intent to catch a batter off balance. It is an illegal pitch.
If there is a runner, or runners, it is a balk when the pitcher makes an illegal pitch.
A quick pitch is an illegal pitch. Umpires will judge a quick pitch as one delivered before the batter is reasonably set in the batter's box. With runners on base the penalty is a balk; with no runners on base, it is a ball. The quick pitch is dangerous and should not be permitted.
Pitchers may disengage the rubber after taking their signs but may not step quickly onto the rubber and pitch. This may be judged a quick pitch by the umpire.
With no runners on base, the pitcher is not required to come to a complete stop when using the Set Position. If, however, in the umpire's judgment, a pitcher delivers the ball in a deliberate effort to catch the batter off guard, this delivery shall be deemed a quick pitch, for which the penalty is a ball. See Rule 6.02(a)(5) Comment.