We know from watching the big glowing MPH at the stadiums that most pitchers throw their fastball in the 90s. I know I’ve never stood at the plate when that happened, but I have wondered how quick that would be. Well, some fine nerds at the Exploratorium Museum of Science have a whole article on it.
During the entire middle portion of the pitch, the batter must time the ball and decide where to swing. If the batter decides to swing, he must start when the ball is approximately 25 to 30 feet in front of the plate. The ball will arrive at the plate about 250 thousandths of a second later — about the limit of human reaction time. The bat must make contact with the ball within an even smaller time range: A few thousandths of a second error in timing will result in a foul ball. Position is important, too. Hitting the ball only a few millimeters too high or too low results in a fly ball or a grounder.