When a batter swings at a pitch and the follow through of his swing brings the bat around and makes contact with the catcher or the ball in back of him on the backswing, it is backswing interference. The pitch will be called a strike only, not interference.
It is commonly referred to as “weak” interference. The contact with the catcher can be with the catcher’s body or his mitt. Being hit by a strongly swung bat is painful and can temporarily incapacitate the catcher, so “Time” is called and the ball is dead. If any runners advance during a play with backswing interference, they must return to their original time-of-pitch base.
On unintentional backswing interference, the batter is not out and the runner returns to his original base.
KNOW THIS: If a batter swings and misses a pitch, then the catcher has the pitch bounce off his mitt and the batter makes contact with the ball and it rolls into fair territory, it is ruled a strike only. The ball is dean and “Time” is called.
Another example of weak interference is when the on-deck batter, base coach or spectator touches a live ball (not a fair batted ball) with no runners on base. In this case, the umpire calls “Time” and the ball is returned to the pitcher.
Insider Reports: Backswing Interference
Can backswing interference and true batter interference happen on the same play? This Insider Report details this strange play as it happened when the Twins hosted the Blue Jays, May 30, 2015.
Backswing interference is a violation without penalty since the batter is only charged with a strike for swinging and missing the pitch. It can be confusing as it was when the Reds Sox and Rays played at Tropicana Field August 23, 2016. Watch the video and read this Insider Report to learn the nuances of this peculiar play.