Watch as Coach explains that catching foul fly ball pop-ups is a skill that needs to be practiced. The catcher must turn their back to the infield on a foul ball behind the plate because the ball is spinning backwards, and you want it to spin into the glove. If the catcher looks straight up for the ball, they have no reference point, and the ball is hard to locate. The catcher must find the back stop then the ball to get a proper line of reference.