Drop Ball after Lookback

[Six_DanO]

Had a situation where B1 on first, pitcher pitches a ball, B1 takes 3 steps towards 2nd, and the catcher immediately throws back to the pitcher that is in the circle. The pitcher looks the runner back, and in the process of turning towards the pitchers plate drops the ball. Question is What options does the runner have/allowed and does it make a difference if the ball stays in the circle or rolls out to the infield? Nothing did occur, just curious what the possibilities were and rulings....

[RKBUmp]

If the pitcher does not have physical possession of the ball the lookback rule is not in effect.

There are also some differences in the requirement of the pitcher having the ball in the circle for the lookback rule between rule sets. Most rule sets is simply possession of the ball by the pitcher within the circle. USA softball requires possession and control of the ball. If the pitcher puts the ball under their arm, between their legs etc in USA softball, they do not have control and the lookback rule is not in effect. The ball must be in the glove or the hand to have control.