On a warm Saturday morning I pulled into the parking lot of a big industrial warehouse in Knoxville, TN. Driving past row after row of cars for an “inflatable party zone” I made my way to the side of the building, parking between a set of stairs and a long set of rusty railroad tracks. Tucked back in the corner of this industrial complex, just a short drive from the University of Tennessee and the vibrant downtown of Knoxville, was a hidden jewel for baseball nerds like myself.

I'd arrived at RBI Baseball, a premier facility where amateur athletes pursue improvement in the hopes of perfection. It’s here, and places like it across the country, where forward-thinking coaches pursue the future of amateur player development. More on that in a bit, though.

The reason for my visit to the RBI Baseball facility in Knoxville was to test the Rapsodo Baseball pitch-tracking unit. The unit, just made available to the public this week, will eventually retail for $3,000, a hefty price tag even in the infamously expensive sport of baseball. So, for $3,000 anyone across the country will be able to track pitches in detail. What does this mean and how does it work?

How It Works

The real hero of the device is the monitor, which captures the baseball using radar (similar components to a Stalker Pro) and a high-speed camera. Data generated by both devices is fed into the onboard software, which translates the raw data into understandable outputs for player and coach.

The Rapsodo Baseball monitor

The unit sits atop a tripod, with all the necessary accessories to ensure the proper angle and positioning of the device. It also includes a heavy-duty metal and plexiglass case designed to protect the monitor from damage on errant pitches (as seen below). I can tell you from personal experience, that this is a useful component.

The unit is set up six feet behind the plate and peers over the catcher’s shoulder to capture the pitch as it travels toward home. It can be connected to a computer or mobile device either via USB connection or Wi-Fi, meaning you don’t have to be within cable length of the catcher to record data—even if the unit does. When each pitch is delivered, the unit captures the requisite data, crunches the numbers, and spits it out into a dashboard that player and coach can use to better understand the pitch that was just thrown.

A sample pitch result

You can see that there’s a lot going on here, but the data should look familiar to anyone knowledgeable about PITCHf/x or Statcast. The top left portion of the screen shows the pitch’s velocity. Directly below it is the number of that pitch in the total pitch count, and then a pitch-type selector where you manually choose which pitch it was that was just thrown.

The top middle section focuses on spin, a popular topic in today’s sabermetric and player development circles. The Rapsodo team has worked to keep the technology and statistics up-to-date, so you’ll see a total spin figure as well as a “True Spin” and “Spin Efficiency” percentage. These should be familiar concepts if you’ve seen the previous work Dr. Alan Nathan and myself have done with spin rate.

The top right section is a movement chart, highlighting the vertical and horizontal movement of the captured pitch. The presentation is exactly like one would expect from PITCHf/x, so this widget should be intuitive for the user.

Finally, the bottom right section is the pitch trajectory, which you can view from the catcher’s POV, overhead, and even from the side. This trajectory visualization also showcases the “spinless” pitch that we so often refer to when referencing pitch movement (in this case depicted as a dashed line). This smart addition allows you to see how the captured pitch compares to a pitch that wasn’t impacted by the effect of spin. This is a terrific edition for a reason that is perfectly captured by the pitch featured in the image above. If you look closely you can see the dashed line crosses right on the edge of the strike zone while the actual pitch moved toward the pitcher’s arm-side out of the zone.

The process of getting data from the unit is painless, as shown in the video below:

The circle in the middle of the screen actually starts spinning as soon as the pitch is captured, meaning the unit is already hard at work before the ball makes it to the plate. A few seconds later and the data is updated throughout the application. You can also see the different options for visualizing the trajectory at the bottom right.

The application records a history of the pitches thrown so that you can go back in and view past pitches to see how they compare to all others you’ve thrown:

One critical component of “how it works” is whether or not it’s accurate. While we did test it against a Stalker Pro 2 radar gun, we didn’t set out to perform scientific testing of the accuracy of the unit. Thankfully, Kyle Boddy of Driveline Baseball has done that for us, and I’ve included some highlights from the analysis performed by Kyle’s team.

In tracking 10 fastballs by both the radar gun and Rapsodo unit, the Rapsodo unit came in 0.1 percent higher than the radar gun. On 10 sliders, Rapsodo came in 0.3 percent lower than the radar gun. In both cases, it was very accurate. On any individual pitch, the unit could miss by a mph or two (the worst offender in Driveline’s study was a slider that the Stalker Pro 2 had at 74.2 mph and Rapsodo had at 72.4 mph). In the words of Driveline: “This showed the final Rapsodo unit and software could very precisely measure the velocity of pitches with no issue.”

Driveline’s analysis also showed that Rapsodo excelled in ways that Trackman cannot. Namely, capturing 12-6 curveballs and low-spin pitches like split-fingered fastballs, forkballs, or knuckleballs. Trackman is intended to be installed in stadiums, like how it's used to generate data for MLB’s Statcast program. Rapsodo is designed for a different kind of usage scenario, one that it clearly excels in.

Full data from Driveline’s tests can be found here, and I would highly recommend their entire post in which they look at the performance of Trackman and Rapsodo.

Another important aspect to consider, when it comes to performance, is accuracy in tracking pitches in the strike zone. Dan Kopitzke of K-Zone Academy–who previously helped with our Axe Bat testing–did some analysis of the Rapsodo’s ability to track pitches in the zone.

Dan compared the Rapsodo to the HitTrax system installed in his facility, which had previously been verified with high-speed camera footage. The HitTrax system uses three high-speed cameras compared to Rapsodo’s one, so he was interested to see if the results would be significantly different.

Overall, Kopitzke found that HitTrax and Rapsodo differed in pitch location by about 1.5 inches on both the horizontal and vertical axes. He notes that is roughly half the diameter of a baseball, well within the margin of error for an umpire calling balls and strikes. I’m inclined to agree with him—while a small difference between the two systems isn’t ideal, it’s not something that you should be overly worried about. After all, no system is perfect, and Rapsodo’s lack of accuracy is largely made up for by its unparalleled portability.

Again, I highly recommend reading Kopitzke’s full analysis here.[i]

Rapsodo and MLB

The applications for major-league teams are seemingly endless. Sure, every team has Statcast and PITCHf/x in their stadium, and many of them have it installed throughout the minors as well. In-game isn’t really a place where Rapsodo can make a difference, but here are just some of the ideas that come to the top of my head:

  • Between-start bullpen sessions to measure fatigue, rate of recovery, etc.
  • When developing a new pitch to add to a player’s arsenal
  • Enhancing existing pitches (e.g., working on curveball spin axis)
  • In spring training to see how pitchers are progressing from the offseason
  • Capturing offseason work for major-league pitchers
  • Private bullpens/tryouts (better than just scouts with a radar gun)
  • Extended spring training to monitor progress of draftees and signees
  • Figuring out which position player to throw in a blowout (just kidding, sort of)

There are dozens more, but the list above is just a quick taste of what Rapsodo makes possible. Rapsodo’s value is most apparent in bullpen sessions, which means that it could become a valuable tool for teams looking to capture data on players between outings or during the offseason and spring training.

Given the budgets major-league teams are working with, a fleet of Rapsodo devices being deployed across their minor-league system seems like a no-brainer, especially since the data it generates would pay off the entire investment if it helps one pitcher become a major-league asset who otherwise wouldn’t have made it. It could also give teams an advantage in trade dealings because it would create even greater information asymmetry about the club’s own prospects.

The Real Impact of Rapsodo

This being a major-league focused website, it makes sense that we’d start by looking at how Rapsodo can be deployed by clubs. The real opportunity, however, comes on the amateur side. In fact, the opportunity to revolutionize amateur baseball is more significant than the incremental benefits that teams might see at the major-league level.

There’s a reason that I started off this review by waxing poetic about the facilities at RBI Baseball. It’s guys like Dan Kopitzke, Kyle Boddy, and the team at RBI Baseball who hold the future of young pitchers in their hands.

RBI Baseball is owned and operated by Nate Headley, the brother of current major leaguer Chase Headley. He has built a terrific staff, and I had the pleasure of spending time and throwing with Kyle Brady, Spencer Shelton, and Arik Sikula. All three guys have professional pitching experience, and threw 20 or so pitches that we recorded with the unit.

Our setup for testing

At RBI Baseball, guys like Kyle and Spencer work with young athletes to help them achieve their goals. For many, it’s being able to play a sport they love in college. Kyle runs The Velo Lab at RBI Baseball, where instructors like he and Spencer use the latest research and technology to inform their ability to coach these young athletes. From their site: “Well researched methods yield the best results. We don't take old phrases and repeat them, hoping for some random outcome. Through detailed analysis and tested methods, VeloLab throwing programs address the needs of the individual for maximum gains.”

This is precisely where Rapsodo’s technology can have the most impact. At $3,000 the unit is still expensive, but nowhere near the costs associated with getting a Trackman unit. Its portability means that facilities can easily set it up, move it around, and even take it to games or practices on the field if needed.

Beyond the unit itself and the accompanying app, Rapsodo has deployed a cloud-based coaching platform (that’s accessible for an additional monthly fee) where coaches have even greater ability to catalog and store data about their athletes. The cloud app currently supports 50 players, 10 coaches (who can each log in and access their players), as well as the ability to capture 1,000 videos that can be paired with data. It stores comments entered by coaches on individual pitches, leaving a track record of mechanical notes or performance anecdotes that can be revisited at a later date.

Today, all of this is theoretically possible—just not in as robust, organized, or evolved form as it is with Rapsodo. The Velo Lab has a Rapsodo unit, but prior to that they largely relied on a radar gun and the eye test. This is no different than hundreds or thousands of facilities across the country, many of whom likely don’t even have a radar gun. With Rapsodo, Kyle and Spencer can dive into the data and use it as much or as little as needed to inform their coaching and feedback for players.

Velocity readings for pitches 76-100 of our study

Storing the data online allows you to see how a player’s performance changes over time, something that’s critical for coaches who work with players over months or years. It also allows coaches to more accurately monitor pitch counts, something that has only been further brought into the spotlight by Jeff Passan’s book The Arm.

What the amateur baseball world needs more of is people like Kyle Boddy, Dan Kopitzke, Kyle Brady, Nate Headley, and so on. It needs people who are willing to test their assumptions, pursue the latest technology, and constantly learn with the goal of providing the best possible coaching to the athletes under their tutelage.

Rapsodo, whether it was intended or not, provides a mechanism for coaches to be more responsible and proactive about the development of the athletes they work with. In the future, Rapsodo plans to be able to e-mail reports and summaries to players after their sessions, empowering the athletes themselves to better understand their data, performance, and their bodies.

Why did I start this review waxing poetic about a big warehouse filled with nets and L-screens that’s situated between a moon bounce emporium and a Norfolk Southern freight line? It’s here that products like Rapsodo’s pitch-tracking unit allow for the greatest gains—if one more player gets noticed and receives a college education or life-changing sum of money because of Rapsodo, then it’s a net positive in my mind. It’s here that the future of baseball is nurtured.


I have a lot of optimism for what Rapsodo can do for the baseball industry. I’m not alone in that sentiment either.

Kyle Boddy of Driveline Baseball:

It is one thing to have a piece of equipment that functions as advertised – and make no mistake, Rapsodo’s unit delivers here – but it’s another thing entirely to have front-line customer service, technical support, and a tight feedback loop with experts in the industry to create an outstanding experience. Rapsodo manages to do both, which is a rare feat indeed in the baseball industry.

Dan Kopitzke of K-Zone Academy:

Rapsodo has been extremely responsive during all of our testing and very appreciative of the feedback. They are a pleasure to work with are very much interested in providing a product that is accurate and reliable. It’s not without its issues but I’m confident that not only will they be resolved but new enhancements and features will be added.

Teams and facilities should strongly consider adding this to their programs if they want to provide objective feedback to their players to aid in their development.

When I worked with Kyle, Spencer, and Arik they all spoke very positively about the prospect of having data to drive their decisions and process. It’s clear that there’s a sense that Rapsodo is working to democratize pitching data for the amateur baseball world, an admirable and important feat.

Still, there are and should be some concerns. One of course is accuracy, something that Rapsodo has improved as they’ve rolled through various iterations of their beta product. The cloud experience isn’t complete just yet—they are offering it for free for the first three months—but there does need to be some user-experience updates that will surely be made once the program is up and running at full capacity.

The biggest concern is about the data itself. With new means of capturing data come questions about who owns that data and what they should be allowed to do with it. Do the players or coaches own the data produced by the unit? Who can share it? With whom?

Eventually it’s inevitable that major-league teams will want to access Rapsodo data in order to fill the black hole that is amateur scouting. The question is how that will work, who gets paid, and what the incentives are to all those involved.

These are complex problems, and ones without clear answers. Still, the promise likely far outweighs the concerns, which can be addressed as the Rapsodo team continues to roll out the product and the accompanying services.


At the end of the day, there’s real promise in the product Rapsodo is bringing to the market. I was very skeptical going in, but I’ve been convinced of the potential for this to change the industry as we know it. What Rapsodo is able to do is either exorbitantly expensive or not available at all. In that way, it’s a clear game-changer.

It’s not without its faults, and there are still a few bumps that will need to be addressed as the product gets rolled out to all audiences. That said, everything I have heard or read from people who have worked with Rapsodo suggests that the company is eager to improve and enhance everything they do as much as possible.

The best way to summarize my experience testing the unit is to share the reactions from friends, colleagues, athletes, and the general public who I’ve shared data, photos, and video with. The unanimous response is "that is so cool." It’s just plain fun to see the data—velocity sure—but also movement and spin.

Considering the implications, it is pretty damn cool.

A special thank you to Kyle Brady, Spencer Shelton, Arik Sikula, and Nate Headley of RBI Baseball and The Velo Lab for having me down and taking the time to help me test the unit, provide your insight, etc. Thanks to Kyle Boddy and Dan Kopitzke for their research and thoughts. Thanks to Kirk Graven for being brave enough to catch me without any protective gear. Thank you to the dozens of people I bounced ideas off of, checked in with, and annoyed with questions throughout this process.

[i] Note: Dan was working with an older version of the Rapsodo software. He plans on re-testing the unit with an updated version of the software and app to see if his findings change.

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