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Building a Pitching Arsenal: Intro + Fastball

The advent of optical ball flight tracking systems like Rapsodo brought with it an array of detailed analyses. These allowed both coaches and athletes insights into the intricacies of baseball athlete performance and development. Perhaps the most discussed and widely used implementations of such insights has been in the design and development of pitches and overall repertoires.

Being able to accurately read a Rapsodo app dashboard has its own benefits. Coaches need to able to take those readings and turn them into impactful feedback. In this series, I will be looking strictly at fitting pitches to an athlete’s fastball and the data points to be mindful of when providing feedback.

As a primer for this series, I suggest reading through the following articles:


While there has been a growing trend among professional pitchers to shy away from using a fastball as their primary pitch, we are going to use a fastball as our starting point in this series. Our pitcher in question is right-handed and throws from a traditional 3/4 release. Below, you will find their average bullpen fastball: 

Velocity (mph)  Spin Rate (rpm)  Spin Direction (hh:mm)  Spin Efficiency (%)  Release Height  Release Side  Vertical Break (in.)  Horizontal Break (in.) 
89.0  2391  00:50  93.4  5.9  2.0  17.2  8.6 

The first thing that should jump out to you is not this pitcher’s total spin rate, but rather their 93.4% spin efficiency. That number needs to improve if this pitcher wants to take advantage of their high raw spin; this will maximize the vertical lift/ride on the pitch and take advantage of their natural ability to spin the baseball.

Luckily, the high raw spin from a sub-1:00 spin direction does allow them to be a bit less efficient and still maintain a decent amount of lift, but this is definitely an area of emphasis. We can attempt to correct this by testing different verbal or visual tools, such as reminding the pitcher to focus on staying square behind the ball or creating spin axis balls (all you need are some good baseballs and a Sharpie!).

The amount of lift on a fastball plays a major factor in determining what kind of secondary offering(s) a given pitcher should employ. For this pitcher, his fastball movement profile would be complemented most by a 12-6 curveball as his breaking ball, which I will explain in more detail in the next installment of this series.

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By Rapsodo Baseball

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