Abstract: An apparatus for training a baseball umpire to visualize a strike zone over a home plate, the strike zone having high and low inside and outside corners. The apparatus comprises a frame, first and second inside baseballs, and first and second outside baseballs. The frame is adapted to extend about home plate. The inside baseballs are coupled to the frame and located such that they are adjacent to the inside corners of the strike zone, respectively. The outside baseballs are coupled to the frame and located such that they are adjacent to the outside corners of the strike zone, respectively. A method of training oneself to call balls and strikes includes the steps of positioning oneself behind the above-described training apparatus, assuming a desired plate stance, and examining the positions of the inside and outside baseballs relative to the home plate.