sipher

x and y: Location of the pitch using the old Gameday coordinate system. I don’t use this at all.
Start Speed, End Speed: Speed in mph of the pitch at 55 feet from home plate and as it crosses the plate.
sz top and sz bot: Top and bottom of the hitter’s strike zone, in feet, as measured by the Gameday system.
px and pz: location of the pitch as it crosses home plate, in feet.
x0,y0,z0: Release point, in feet.
break y, break angle and break length: Measures the direction and magnitude of the movement on the pitch. I’m still trying to figure out how these values work to represent what the pitch is doing.