One of the situations that I don’t feel like I have a grasp on is batter’s interference – you don’t see it much. Someone posted this quote from Jim Evans on a forum at Umpire-Empire and it explains the rule as pretty cut and dry: anything other than just standing still in the batter’s box that hinders the catcher should be ruled interference:
making any movement which obstructs, impedes, or hinders the catcher’s play in any way. A swing which carries the batter over home plate and subsequently complicates the catcher’s play or attempted play should be ruled interference. Contact between the batter and catcher does not necessarily have to occur for interference to be ruled. Merely blocking the catcher’s vision to second base may very possibly be interference.A batter shall not be charged with interference for standing still and consequently complicating the catcher’s play at any base. If he is within the confines of the batter’s box, he must make some “other movement” that is deemed a hindrance to the catcher’s play before interference is ruled. ……
SITUATION: One out…runner on second. The runner is attempting to steal third on the pitch. The batter tries to get out of the
catcher’s way by stepping out of the batter’s box. However, this movement hinders the catcher’s throw. The runner is safe at third. There was no intent to interfere. What’s your ruling?
RULING: Intent is not relevant. The batter is out for the interference and the runner must return to second.