How a polarizing hitting approach took over MLB, and what happened when it stopped working for a top prospect

The press room at Fenway Park filled with the kind of optimism that comes with believing you got something right.

It was so soon into a young career. Just eight games to be exact.

But Craig Breslow sat behind a microphone, Red Sox team president Sam Kennedy to his right. Between them was Kristian Campbell, 22 years old, staring ahead toward a future the Red Sox believed had already begun.

Boston just signed him to an eight-year, $60 million extension.

"Here we are today sharing a massively significant moment for this organization," Breslow said on April 5, 2025.

This wasn't merely a celebration of Campbell. It was also a validation of a player-development philosophy the Red Sox had increasingly embraced.

Near the end of Chaim Bloom's tenure as top executive in 2023, the Red Sox began incorporating principles developed by Driveline Baseball, a private player-development company that uses biomechanics, technology and data to identify ways players can move more efficiently and, ultimately, perform better.

Led by Paul Toboni, then the Red Sox vice president of amateur scouting and player development and now the Nationals' president of baseball operations, Boston began incorporating Driveline's principles into its developmental system. That meant altering…

Original source: https://www.cbssports.com/