7 Simple Steps to Evaluating Baseball Pitch Movement

baseball pitch movement

The introduction of new tech like Rapsodo cameras is changing the landscape for pitchers at all levels. Until recently, most pitchers would focus on their pitching mechanics and strength training.  Now, technology is bringing a whole new realm to pitching at the point of release and we have a third leg on the stool that can’t be ignored.   So, let’s review how, 7 simple steps, we go about evaluating baseball pitch movement.

Note: All reference to ball pitch movement in this article are from a righty pitcher’s viewpoint.  If you’re a lefty just flip the charts over (side-to-side).

Those who learn how to take advantage of this are going to jump leaps ahead of those who don’t.  The crux of the new tech is not only in the new information, but also in the instant feedback that you can receive during training sessions.

Working with our pitchers in our Pitch Design program, the first thing we do is collect what I call the pitcher’s DNA.  Every pitcher has a certain way they throw the ball. Some are over the top, some are ¾, some are side-arm guys and on and on.  Each one has a distinct baseball pitch movement pattern across his repertoire.  Between the arm slot, elbow flexion, wrist position and grip, fingers and final release, you can see how every pitcher is different in every way.

To get a good read on a pitcher’s DNA off the Rapsodo camera, it generally requires a full bullpen with at least a dozen pitches by pitch-type.  From there, we break it down into several components and review each piece of information in-depth.  It’s basically like preparing a game plan.  Let’s go over step-by-step what we look for and how we assess the results:

    1. Spin Efficiency %s
    2. Baseball Pitch Movement Patterns
    3. Differentiation and Relative Movement
    4. Holes in the Movement Pattern
    5. Consistency of Pitch Axis by Pitch Type
    6. True Spin Rates
    7. Arm Slot (Release Height and Side)

Let’s get started…

1. Spin Efficiency % (SE)

The first thing we look at is the SE% numbers across the various pitches.  It represents to the percentage of a baseball’s “total” spin rate that contributes to its movement. But before we go any further, let me say that the name, “Spin Efficiency”, is a total misnomer.  One would think a higher efficiency is a good thing, but that’s not the case with SE%.  A higher SE% is not necessarily better.

In very simple terms, at any given time a baseball can be spinning in three different directions, backspin/topspin, side-to-side and/or spiral (like a football).  Without getting into much detail on how Spin Efficiency is calculated (click here if interested), you should know that each pitch type, with a different expected baseball pitch movement pattern, has different ranges of SE% that would be deemed appropriate.  For example, a fastball could have SE%s approaching 95-100%, while a slider could be in the 20-35% range.

Here are a couple general comments on SE% results:

    • First, we look for excessive cutting on the 4-seam, 2-seam or change-up. When a pitcher’s average SE% drops below 80-85% we begin to evaluate adjustments.  It’s not necessarily an easy fix given how fast the hand is moving at the point of release, but a low SE% on a 4-seam or 2-seam is taking both movement and velo off the ball as you’re cut it during the release.
    • Then, we evaluate whether the % numbers are appropriate by pitch-type? As I mentioned earlier, each pitch type is expected to be within a certain range.  So, we would need to make sure we are within the proper range (click here for some examples).

Generally speaking the higher the SE%, the more the movement on the ball.  The chart below is a good visual.  You should generally expect SE% to go up as you move outwards on the movement chart.  But as I mentioned, this metric is pitch-specific.  Certain pitches by design are expected to have higher movement than others.  The closer they get to dead center the lower the SE%.

Baseball Pitch Movement

2. Baseball Pitch Movement Patterns

Next up on the list is movement patterns.  Everyone knows a 4-seam should move differently from a 2-seam.  But until now, the degree to which they truly differed was only available with whomever could afford a Trackman.  You could possibly see a difference with your eyes.  But you couldn’t really measure it.

We now know that the eyes don’t even come close to seeing everything on a pitch.

Let’s first go over some basics.  All ball movement in the data world is measure against a “hypothetical” pitch which doesn’t move at all.  This pitch is generally referred to as a gyroball with 100% spiral spin (with a SE of 0%, click here for more on gyroball).  You can think of the gyroball as a frame of reference on the movement chart.

The following chart is what you could generally expect for different pitch types. The regions designate an approximate movement area.  For example:

    • 4-seam (dark blue) with back spin is moving arm-side, up and in
    • Curveball (purple) on the bottom is moving glove-side, down and away
    • Gyroball (black dot) is our reference point at dead center

Baseball Pitch Movement

Having said that pitchers could easily fall outside the designations above.  A side arm pitcher, or one with an over the top delivery would likely have a completely different profile.

3. Differentiation and Relative Movement

When evaluating baseball pitch movement patterns, we look for pitch differentiation.  The idea being that pitches should move differently and away from each other (hence tunneling).  You’d be surprised how many pitchers’ 4-seams, 2-seams and even change-ups move the same way.  Here is an example of an advanced high school D1-bound pitcher who throws exceptionally hard, but our initial read highlighted how 3 of his pitches moved the same way (by the way we fixed this).  You can’t imagine how often we see this from the youth level all the way through the college ranks.

I know baseball is a game of inches, but the three pitches in the chart above are pretty much the same pitch from the batter’s standpoint. If you’ve ever wondered why certain pitchers get hit second time through the line-up, then don’t guess any longer. I am willing to bet it’s in their movement pattern.  I don’t care what the grip looks like or where the arm slot is at delivery.  From a ball movement standpoint, the only thing that matters is how the ball crosses the plate.

4. Holes in the Movement Pattern

Pitching is difficult enough, but if you have mastered a few pitches and would like to expand your arsenal there is no better way than working with pitching data and instant feedback.  Here is a chart of a D1- level player who came to us with three high-level pitches.  A quick look at this chart shows he could possibly benefit from a slider or a cutter.  If he were to successfully develop such a pitch, it would be highly incremental to his overall movement pattern.

5. Consistency of Spin Axis by Pitch Type – Rapsodo reports provide data on an average and pitch-by-pitch basis.  Another set of data we like to review is the consistency of spin axis vs. the average (sort of a standard deviation).

As you can imagine, every thrown pitch is different from the prior.  But, with specific pitch types we look to see how well a pitcher is repeating his throw.  One way to look at this is to review the consistency of the spin axis from 4-seam to 4-seam or curveball to curveball.  A professional ball player is going to have a much higher level of consistency on his 4-seam than a high school player.  Nonetheless too much variation could imply mechanical and/or physical issues which are prohibiting the pitcher from repeating this mechanics on a consistent basis.  That’s when we go back to items one and/or two on the list at the beginning of this article.

6. True Spin Rates

A lot has been written about the value in spin rates and although our data set is somewhat limited, we have a pretty good idea what high school and D1 level pitchers “True” spin rates generally might look like (click here for more info on “True Spin”).  Comparing a pitcher’s results to a 4-seam data set like below can help show pitchers how they fare in comparison and whether they should utilize certain pitches more or less often depending on their True Spin rates and movement pattern.

7. Arm Slot (Release Height and Side)

With Rapsodo 2.0, you can now get specific arm slot data in relation to the ground and the center of the plate.  The measurement basically provides a tool for assessing the consistency in the arm slot from pitch to pitch.  It’s a great way to make sure that tour arm slot is remaining consistent as you go from  a fastball to a curveball to a slider.  The measurements generally should be within a few inches from one another from pitch to pitch.


Now, let’s bring this all back into some perspective.  As I mentioned earlier, assessing pitchers using data opens a whole new realm.  It will not only give you a true assessment of your movement pattern, it can also open new areas for improvement.

Case in point is our own pitching coach Robbie Aviles who spent 7 years with the Indians.  As a reliever with the Indians he primarily threw a 4-seam, change-up, sinker and slider.  Although he doesn’t pitch any longer, this is what he has been able to do over the past 6 months.  He did this through a continual reassessment of his pitches on Rapsodo with instant feedback on a pitch-by-pitch basis.

Baseball Pitch Movement

At this point, his overall movement pattern is off the charts.  He often says he wishes he had access to this type of assessment and info when he was initially drafted when he was 18 years of age.

By Bahram Shirazi (BSEE, MBA, Co-Owner RPP)