There are many variables that influence the effectiveness of a pitch. Of these many variables, the way in which the pitch moves contributes to the overall story of a pitcher. And because we all want to know how and why a pitcher is successful, determining benchmarks for movement can be a useful measurement when evaluating pitchers.

Using 2011-2013 data, with exclusion criteria of at least 50 innings and the pitch being thrown at least 4% of the time, we determined the average horizontal movement, vertical movement, and overall movement (which we refer to using the Z-axis) of each pitch. Horizontal movement is affected by handedness; so to account for that, we used the absolute value of average movement. All of this doesn’t mean much yet, because there are so many factors that goes into what makes a pitch effective. But we can at least look at it to get some idea of how a pitch moves relative to others throwing it.

Here they are:

FA% vFA FA-X (inches) FA-Y (inches) FC-Z (inches) 38.99% 91.48 4.82 7.73 9.49 FT% vFT FT-X (inches) FT-Y (inches) FT-Z (inches) 21.06% 91.31 8.50 6.76 11.04 FC% vFC FC-X (inches) FC-Y (inches) FC-Z (inches) 19.07% 88.44 1.27 5.47 5.83 SI% vSI SI-X (inches) SI-Y (inches) SI-Z (inches) 36.84% 90.23 8.57 4.91 10.31 FS% vFS FS-X (inches) FS-Y (inches) FC-Z (inches) 14.66% 84.09 5.31 2.82 6.43 SL% vSL SL-X (inches) SL-Y (inches) SL-Z (inches) 21.27% 83.21 2.67 0.44 3.64 CU% vCU CU-X (inches) CU-Y (inches) CU-Z (inches) 14.56% 76.89 5.01 -5.86 8.02 CH% vCH CH-X (inches) CH-Y (inches) CH-Z (inches) 12.82% 83.10 7.01 4.14 8.55

You may notice it to be odd that some of these pitches’ vertical movement appear to rise. However, these measurements do not account for gravity. If gravity was factored into the measurement, then yes, the slider (and the rest of all these pitches) would appear to drop many more inches.

Lets see how Clayton Kershaw’s curveball matches up…

CU% (pfx) vCU (pfx) CU-X (pfx) CU-Y (pfx) CU-Z (pfx) 14.52 74.94 2.7 -8.58 8.99

Versus MLB average.

CU% (pfx) vCU (pfx) CU-X (pfx) CU-Y (pfx) CU-Z (pfx) 14.56% 76.89 5.01 -5.86 8.02

Kershaw’s curveball, although the horizontal movement is less than average, moves much more than league average vertically and more overall.

Work in collaboration with Douglas Wills.