While the vast majority of interference infractions are committed by the offense team (batter, runner), there is a common way for a defensive player to be charged with interference. It is commonly called catcher’s interference.
The defensive interference rule specifies that a fielder may not hinder or prevent a batter from hitting a pitch. The most common violation of this rule is when the batter swings at a pitch and the bat touches the catcher’s mitt.
However, the bat doesn’t have to touch a catcher or his glove to be catcher’s interference. If the catcher leaves the catcher’s box early, he might interfere with the hitter without contact. Although the hitter does not have to offer at the pitch, he has to show interest in offering at it and that he was hindered or prevented by the catcher.
Insider Report: Catcher’s Interference
In this Insider Report, Rich Marazzi does a great job explaining an unusual component of the catcher’s interference rule.
Catcher’s interference is a delayed dead ball – meaning the offensive team is can choose to accept or decline it based on the results of the play. If the offensive team accepts the interference, the batter is awarded first base and the catcher is charged with an error.
Ted Barrett explains the options open to the offensive manager related to a catcher’s interference call
Proper mechanics for an umpire making a catcher’s interference call.
On catcher’s interference the umpire makes no verbal call until the play is dead.
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