Pitcher's Effective Velocity

A pitcher can add or subtract 4-6 mph by throwing his fastball to different locations!  The FB up and in has the highest effective velocity according to Perry Husband, Baseball Analyst.
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Perry Husband's model is based on the arc of hitters' swings, and the understanding that bats must move farther to reach pitches on the inner part of the plate than on the outside edge. Put another way, a batter can hit an outside fastball as it crosses the plate, but to make solid contact with an inside fastball, he must reach it much sooner — up to 2 feet in front of the plate — which requires the hitter to move the bat a greater distance in less time. With this detail in mind, it makes sense to build an approach based not on a pitch's radar speed, but how quickly the man standing in the batter's box can react to it.

There is an imaginary stripe that runs diagonally across the strike zone, from the batter's feet to shoulder level in the opposite batter's box, where a pitch's EV equals its actual speed. Husband calls this the Zero Line. He calculated that for every 6 inches the ball moves closer to the hitter from that line, it picks up 2.75 EV mph; for every 6 inches it moves away, it loses an equivalent amount. This gives strikes thrown at identical speeds on a given horizontal plane about a 6-mph fluctuation in reactionary speed from one end of the strike zone to the other. Add vertical differences into the equation and that spread can easily double, all for pitches that are thrown at the same actual speed!