Bahill said hitters he's spoken with about the illusion of the rising fastball remind him of an audience at a magic show. But a baseball does not disobey the laws of physics, no matter who throws it. The hitter develops a mental model of how fast the ball is traveling, its course and where it will be when it crosses home plate. The batter underestimates the pitch speed and therefore incorrectly predicts the height of the ball when it enters the hitting zone, he said. The batter takes his eye off the ball for an instant to look at the predicted point of ball-bat collision and when the ball comes back into view it is higher than he thought it would be.
Batters often say the ball hopped, or exploded.
Since Bahill has not played much baseball himself, he is a poor candidate for matching theory to reality. It therefore seemed prudent to consult that esteemed professor of hitting, Tony Gwynn. I know the ball is falling the whole time. Presented with Bahill's three phases of hitting, Dr. Gwynn nodded knowingly. The third stage, he noted, is executing the swing.