"Catcher's interference" is called when the catcher physically hinders the batter's opportunity to legally swing at a pitched ball. This occurs most often when a catcher squats too close to home plate, so that the batter's bat touches the catcher's mitt as the batter swings. This is most likely to happen on attempted steals where the catcher is anxious to catch the ball as soon as possible and may move his entire body or mitt forward a bit. It also more commonly happens to hitters, such as Jacoby Ellsbury, (who holds the record for the most times interfered with by a catcher in both a single season and his career ) who frequently let pitches get deeper and take later swings.