By Alex Brandon/AP.

When David Gavant helped produce a look back at Cal Ripken’s career for Major League Baseball Productions, he and his co-workers wished they had a crew following Ripken’s career from the beginning.

When Jess Atkinson began tailing Bryce Harper during the very first days of his professional career, he quickly decided there was something grander than minor-league footage playing out in front of him: that there was a film to be made.

And when Gavant and Atkinson’s teams ultimately decided to collaborate, that movie became a reality. “Bryce Begins,” an hour-long look at Harper’s progression from teenage wunderkind to Major League star, will debut on ESPN Tuesday night at 9.

The film draws on MLB Productions’s access to the imagery and behind-the-scenes footage of Harper’s time with the Nats, and the hundreds of hours Atkinson spent with Harper and his family in 12 different cities over the past two years. It draws on a half-dozen lengthy sit-down interviews with Harper, countless casual encounters, and interviews with Harper’s father Ron, agent Scott Boras, high school coach Sam Thomas, teammate Ryan Zimmerman, Ripken, Mike Trout and many others.

“I felt like we were with him in that very small window when you undergo that transformation from being a boy or a young man to being your own man,” said Atkinson, the former Redskins kicker and WUSA sports director and one of the founders of 3 Penny Films, which teamed with MLB Productions on the movie.

“To be able to document somebody’s career from that first chapter, we’ve never done this before,” said Gavant, the executive producer from MLB Productions. “We’re hoping there are many chapters of this book, so to speak, so that we can continue to add to this story.”

The Harper film will put the Nats on ESPN three nights in a row; their games with the Braves on Monday and Wednesday will both air on the network at 7 p.m.