Once Hudson took his mask off and started walking towards Williams, then Harper absolutely should have been allowed to leave the box. In fact, it's what you'd want him to do. If Hudson jawed at Harper about leaving the box after he left his spot, then that is ridiculous. It is ridiculous too that he called that a strike after the even more ridiculous ball called as a strike the night before. It neutralizes Harper's talents if they aren't going to let him take walks anymore.