pro 3.0
seam orientation

Introduction to Seam Orientation: How to Apply the Data to Pitch Design

April 28, 2023
A pitcher’s primary goal is to deceive hitters by developing an arsenal with multiple pitch types, so hitters don’t know where to swing to make solid contact.  

For over 100 years, we have understood the forces that affect the movement of a pitched ball to be drag, Magnus and gravity. Additionally, the defining characteristics of a pitch type included velocity, spin rate, and break; all metrics measured by Rapsodo. Now we can add a new metric to that list: seam orientation.  

Research on the aerodynamics of baseballs conducted at Utah State University’s (USU) Experimental Fluid Dynamics Laboratory widened our understanding of the forces acting on a pitched baseball by introducing us to the Seam Shifted Wake (SSW) Effect. The SSW Effect is created by seam orientation. 

Let’s dive into seam orientation and 3 ways pitch design can benefit from it.  

What Is Seam Orientation? 

The orientation of the seams on the baseball can have a significant impact on the ball’s movement and the way the pitch is perceived by the batter. This is what we mean when referring to our seam orientation metric: the position of the seams about the spin axis. Another way to think of it is we are showing the point on the ball that the ball is rotating counterclockwise about. 

Adjusting the seam orientation of a pitch can result in more movement due to the SSW force acting on the ball, ultimately changing the trajectory and subsequent break numbers. 

The research conducted at USU has deepened our understanding of the physics behind how and why this works. This research has helped us understand why pitchers need to pay attention to seam orientation, and why it’s important for Rapsodo to measure and report it as a tool to aid pitchers in pitch design. 

3 Ways to Improve Pitch Arsenal with Seam Orientation & Rapsodo PRO 3.0

When it comes to the three ways that seam orientation can help with pitch design, the first thing to know is the "ideal" seam orientation is going to look different from pitcher to pitcher and pitch type to pitch type. Each pitcher may have a different optimal seam orientation for the same pitch type. This is due to the SSW Effect being a function of pitch metrics in addition to seam orientation like velocity, spin rate, spin direction, and gyro degree. The SSW Effect is also a function of characteristics of air and the ball itself, like ball roughness and seam height. 

 Using seam orientation to effectively maximize break and know what break to expect for each pitch is going to take experimentation. Experimentation is not new to pitchers, it’s something they have always done. Rapsodo’s seam orientation metric is just another tool to help you more efficiently experiment as you build your ultimate pitch arsenal.

Immediate Feedback

Before the new seam orientation visual feature in the Diamond App, made possible by advancements in the PRO 3.0, pitchers would simply have to remember how they gripped the ball to get it spinning the way they wanted it to. Some even had to take notes the old-fashioned way with pen and paper.  

Rapsodo's new Diamond App feature provides immediate feedback by showing pitchers a visual of how their pitched ball is spinning, how it was orientated, and the break as a result of those factors.

Remembering how you hold the ball by taking notes on how you hold it or taking a picture of the ball in your hand are all qualitative ways to experiment with seam orientation. By quantifying seam orientation, we can more efficiently experiment because we can look for correlations between seam orientation data and break data. Quantifying the data can also help a pitcher analyze how consistent they are.

Looking at these things together, we can see whether a certain seam orientation helps a pitcher get the movement they are looking for and which seam orientation works the best. The instant feedback of their performance gives pitchers the confidence to replicate the seam orientation and make the changes needed to see immediate results.  

 Historical Data

Rapsodo's Cloud Platform records and saves every pitch so pitchers can go back and dive into the data. Using the saved seam orientation data, we can see how good pitchers are at replicating their desired seam orientation to get the repeated break they are looking for. The more often we can replicate these movements, the more confident pitchers will become. 

Data points like Vertical and Horizontal Break can highlight how to maximize movement on pitches. An examination of the historical data via Rapsodo’s seam orientation plots will help pitchers find their optimal seam orientation for each pitch type.  

As pitchers and coaches learn to incorporate seam orientation, pitch design will become more efficient with data-driven analytics, giving pitchers more consistency with their pitch arsenal. 


Increasing pitch movement is the goal of every pitcher and Rapsodo’s seam orientation is the latest tool to aid pitchers in that quest. By utilizing this data, pitchers who lack elite velocity or elite spin rates can still develop pitches with elite movement, and elite pitchers can now become even more effective. 

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By Rapsodo Baseball

With an unwavering passion for the game and data-driven insights, we're here to inspire and elevate your Baseball journey through articles that help you find improvement and excellence.