PRESCOTT, Ariz. -- Dennis Tiefenthaler’s vision can be read and downloaded.

Tiefenthaler and his son, Jared, collaborated on a book and training app that delves into seam reading for baseball and softball. The book -- “Seam Reading: The Hidden Art of Hitting” -- was released on Feb. 1. The corresponding Seam Reader app, which debuted on April 2, complements the book with visual images to demonstrate the art of seam reading.

“It was pretty much designed as a training mechanism to get kids to learn these pitches at an earlier age,” said Dennis Tiefenthaler, who is an Armour native. “Instead of just guessing up there.”

The book and training app teaches hitters how to learn the face of pitches, their spins and rotations. The two platforms are designed to answer the question for batters: Are you a seam reader hitter or a guess hitter?

“We just wanted to get out and make it known that this skill is possible,” Jared Tiefenthaler said. “It started somewhere and where it can go and how important it is to coaches, players and parents.”

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The idea was sparked more than 30 years ago when Dennis was playing in the California Angels organization. Tiefenthaler was struck out by a former teammate on a slider. After the game, Tiefenthaler’s former teammate boasted that he should have known it was a slider.

Tiefenthaler was struck by the comment and sought out advice from then-manager and current Angels manager, Joe Maddon, who assured him he was taking the right approach.

“He said, ‘No, you were taught how to read pitches and what he’s talking about is guessing what is coming next,’ ” Dennis Tiefenthaler, 57, said.

The incident stuck with him. After his two-year minor league career, Tiefenthaler got into coaching and conducting hitting lessons. He discovered seam reading wasn’t widely known and it was eating at him to do something about it.

Tiefenthaler attempted to get a book done in 2003, but couldn’t get the ball rolling. He eventually bought the Seam Readers domain name and started the process again in 2013. The 94-page, independently published book was completed 2 1/2 months ago.

“Our mission is to teach kids the faces of these pitches,” Dennis Tiefenthaler said. “It’s something you can’t argue. Their coaches can’t say what we are instructing or what we are showing you is incorrect because it’s not.”

Los Angeles Angels manager Joe Maddon, left, holds a copy of Dennis Tiefenthaler's book at a spring training game. Tiefenthaler is at the right.
Los Angeles Angels manager Joe Maddon, left, holds a copy of Dennis Tiefenthaler's book at a spring training game. Tiefenthaler is at the right. (Courtesy photo)

Book and training app take off

The book is broken into 18 chapters and different three sections: Validation, Seam Reading and Balls and All. Tiefenthaler revisits his high school, college and minor league playing days in the first section.

Tiefenthaler was a multi-sport athlete for the Armour Packers, earning all-state honors in basketball, football and powered them to back-to-back Class B track and field titles in 1978 and 1979. The Packers also won state basketball titles in 1978 and 1979 with Tiefenthaler on the team.

The Toronto Blue Jays drafted him in the 19th round of the 1980 Major League Baseball Amateur Draft. After he played baseball at Yavapai College in Prescott, Arizona, Tiefenthaler was drafted in the second round of the 1982 draft by the Baltimore Orioles.

The second portion of the book dives into seam reading and has seven chapters dedicated to the skill. The father-son duo came up with varying philosophies and sayings throughout the book. They are broken into different chapters in the second section.

For example, one chapter is titled “Rotation Before Location, True Pitch Recognition.”

“Seam Readers worry about rotation before location,” Dennis Tiefenthaler said. “You have to know both of them within an instant of each other, but we want to know the rotation before the location. We’ve come up with (a saying that) a four-seam fastball looks the same today as it did 100 years ago when Babe Ruth was playing. It’s fact.”

The final portion has two chapters with still images of 12 different pitches -- six baseball and six softball -- to demonstrate the mental process of seam reading.

“No other book has ever done that,” Jared Tiefenthaler said. “There’s never been still images of moving pitches.”

Jared tried to use Black Hills State’s photo equipment — valued at $50,000 — to film rotations of a moving pitch. The images were too blurry and a slow-motion camera couldn’t properly execute their plan. They needed images spinning at a fast rate to make it work.

He connected with Patrick McCaffrey, who is a 3D generalist special in Maryland. McCaffrey created pitching rotations at 2,000 revolutions per minute and what it looks like from the human eye perspective. The still photos are in the book and the video images are in the app to go hand-in-hand with each other.

A four-seam fastball image from the Seam Reader app.
A four-seam fastball image from the Seam Reader app. (Courtesy photo)

“They do complement each other,” Jared said. “The book is for the parents and the coaches, the history of the skill and just letting it be known that it’s out there. Whereas the app is the direct training tool for the player and that’s kind of how they correlate.”

But Jared decided to take it a step further. Jared, who played college football at Glendale (Arizona) Community College and Black Hills State University, spearheaded the training app.

“It was a big learning process -- definitely,” said Jared Tiefenthaler, who majored in business administration with an emphasis in entrepreneurship. “It was a lot of fun going through it with my dad and figuring out things day-by-day basically and getting to where we are now. We’ve built a great team in our company. We have marketers, developers, graphic designers, animators and a bunch of people who are helping. It’s an awesome experience building a team more than building the app. The app kind of came all together with the team.”

The app received nearly 10,000 downloads in the first few weeks. Seam Readers are also on Instagram, Twitter and Facebook.

It’s picking up steam, too. The app was originally intended for younger baseball players, but the Texas Rangers’ hitting coordinator has the whole organization using the app, Dennis said. Josh Jung, who was the Rangers’ 2019 first-round pick, is an avid user of the Seam Reader app.

The book is on and the Tiefenthalers’ website is The book has endorsements from Maddon and MLB’s all-time hits leader Pete Rose, who is recorded on video supporting the method on their social media platforms.

“Jared will tell you Pete Rose did it innately,” Dennis said. “He didn’t know he was doing it necessarily because he never guessed. This was pretty much it all came out to help kids learn these rotations or learn what these pitches look like at an earlier age.”

It’s also helping the father and son achieve their dreams. The father’s vision of seam reading has taken off, while the son’s dream of owning a business is coming to fruition.

“It’s been such an experience greater than I could have imagined because it’s making my dad’s dream come true, while in turn making my dream come true,” Jared said. “It’s so cool because I’ve known about this idea since I was a little kid and now I am actually the one getting it done for my dad. That’s just such a cool opportunity for me and a blessing.”