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 a hitter's swing path to produce more balls in the air, particularly to the pull side. It meant increasing bat speed and improving how efficiently the body generates and transfers that speed.
Campbell was the system. He was the example. More than other top Red Sox prospects Marcelo Mayer or Roman Anthony, Campbell allowed the organization to flex what player development could look like when viewed through the lens of data.
Through Driveline.
Mayer and Anthony were the better bets. Campbell, a fourth-round pick out of Georgia Tech in 2023, was different. Boston could point to what he had been, what its development apparatus identified and, ultimately, what it helped create.
"What he was was a good player who made himself a great player because of his work ethic, diligence, open-mindedness and attitude," Breslow said at that press conference 17 months ago. "In many ways, he is a prime example of what's possible when great scouting meets great development around a player who prioritizes maximizing his potential."
That's not how the story played out, though.
Fast forward to June 2026, more than a year since Campbell had last stepped onto a big-league diamond. The seat behind a microphone and a slew of reporters at Fenway Park had been replaced by a dusty wooden bench in Worcester, Mass., and an audience of one reporter.
Campbell's major-league career has not lived up to the promise. He hit .301 with a .902 OPS and four homers in his first 29 MLB games. Then he stopped hitting.
Campbell followed that up with a .159 batting average and a woeful .465 OPS in his final 38 games before being exiled to the minors. He's been in Triple-A Worcester since June 21, 2025.
MLB pitchers found holes. They adjusted. Campbell struggled to adjust back. One source suggested Campbell's former teammate Alex Bregman played a role in tinkering Campbell's swing. Bregman, a three-time All-Star now with the Cubs, was a mentor for Campbell during his time in Boston. Bregman possesses a wealth of hitting knowledge but is also known as the ultimate tinkerer, and some believed that Campbell began tinkering too much himself and changing his swing for the worse.
Another evaluator, however, scoffed at that: "Bregman didn't hurt Campbell. Sinkers did."
When the Red Sox demoted Campbell, the club tasked John Soteropulos, a former Driveline hitting trainer and now the hitting coach for the major-league club, with helping Campbell find his way back. But Campbell never returned to his dominant form, and one source said he felt even more confused at times. He hit a modest .273 with a .799 OPS and eight homers in Triple-A to close out 2025.
Campbell's roller-coaster career is a prime example of a belief in the industry: If Driveline wants to take credit for players' ascents, it better take ownership of the struggles, too. And Campbell is hardly the only test case. Across baseball, the rise of modern, data-driven player development has produced success stories. It has saved careers. It has also frustrated players and disrupted growth. Its influence has, rightfully, become deeply embedded in the game. But the approach has sometimes shut out or quieted coaches and players who weren't fully on board. The question is no longer whether Driveline and the movement it helped popularize have changed hitting in recent years. It's what the game has gained, and may have lost in the process.
In Campbell's case, the scouting report eventually outdueled the system, and for the first time in his rapid climb through professional baseball, the player who worked tirelessly, perhaps too tirelessly, to maximize his potential was searching for answers.
"Some of the stuff I ran into recently, or even last year when I was in the majors, was more just different pitch types I haven't seen before," Campbell said earlier this summer.
Campbell's rise was emblematic of both his talent and the developmental system that helped shape him. But to understand how Campbell became the player the Red Sox believed was worth $60 million, one must first understand the philosophy that helped unlock him.
Among a seemingly endless collection of beige buildings in Scottsdale, Ariz., sits one of Driveline Baseball's training facilities. From the outside, there is little reason to suspect that within this nondescript commercial complex is an operation that has had an outsized influence on Major League Baseball's front offices and player development systems.
Driveline was founded in 2007, and for years, its influence was felt primarily on the pitching side. Driveline developed a proven track record of increasing velocity while teaching pitchers to throw their best stuff in the strike zone.
Driveline's rise was led by founder Kyle Boddy, whose unconventional path into baseball included professional gambling, blackjack card counting and online poker. Boddy never played or coached professionally. He didn't play in college, either, dropping out of Baldwin Wallace University before bouncing through jobs in tech and data science and eventually launching Driveline.
To many in baseball, the idea that someone with Boddy's résumé could challenge the infrastructure that stood before him drew skepticism. But decision-makers eventually looked beyond it and delved into the biomechanics and data at the heart of his system.
"If we had any sort of lasting influence or whatever was first, I think it was just player development, data-driven player development," Boddy said. "We did it the best. I still think we do it the best." Boddy served as a special advisor for the Red Sox from 2024 until this June and has also worked for the Reds. He hopes to one day run a team as its general manager.
At its core, Driveline is built around the idea that skillsets and, ultimately, production, can be improved through technology, biomechanics and training methodology. After seeing results with pitchers, Driveline began applying those principles to hitters, too. The company believed that bat speed, launch angle at the point of contact and body positioning were among the tools that could be measured and improved to create a more productive hitter.
Inside the facility, exposed wires connected to high-speed cameras provide instant feedback on a hitter's swing. Sensors attached to bats detail how the barrel moves through the zone. On this spring day, a group of independent league players trained alongside former big-leaguer Rowdy Tellez, who was preparing to play for Mexico in the World Baseball Classic.
Three training bats rested inside the cage, their barrels colored green, red and blue, all meant to help hitters increase bat speed and barrel control.
The green one was barrel-loaded, 20% heavier than a player's normal bat, with the additional weight concentrated near the barrel. The added weight forces hitters to use more of their bodies throughout the load and into the swing, rather than simply throwing their hands at the ball. The red bat was also 20% heavier, but with the additional weight concentrated near the hands, helping hitters who fire too quickly keep the barrel through the hitting zone longer. Finally, the blue bat was 20% lighter than a player's game bat, allowing hitters to move it faster through the zone and become accustomed to generating greater bat speed under control.
"We don't want to live in a world where the hitter has to have perfect timing all the time," Driveline hitting coordinator Jacob Hirsh said.
The approach initially did wonders for Campbell. It's worked great for Toboni's new team in 2026, too.
When Toboni arrived in Washington as the Nationals' new head of baseball operations leading into this season, he helped modernize the organization's biomechanics and data systems, areas that had lagged under former president of baseball operations Mike Rizzo.
Under Toboni, the team overhauled its hitting staff, hiring lead hitting coach Matt Borgschulte, who served as the Twins' hitting coach the year prior, alongside assistants Andrew Aydt and Shawn O'Malley. Both Borgschulte and O'Malley came from traditional baseball backgrounds. Aydt's path was less traditional: he worked at Driveline from 2018 through 2025 after playing Division II baseball at McKendree University in Illinois.
And Aydt wasn't the only Driveline connection. Toboni also hired Travis Fitta, a Driveline employee from 2023 to 2026, as the club's Triple-A assistant hitting coach (Fitta has since left to become the hitting coach at Grand Canyon University).
The team has faded in the wild-card race, but through Aug. 25, the Nationals led the majors in home runs (184) and runs scored (695) and were third in OPS (.756). A year ago, the club owned a .693 OPS, a mark that ranked 24th in baseball.
Nats star James Wood, prior to and oblique strain that sidelined him for nearly all of August, took even greater strides, batting .265/.393/.535 with a .928 OPS and 30 homers. CJ Abrams has put together his best season yet, emerging as one of the top-hitting infielders in baseball while batting .267/.343/.502 with a 130 OPS+ and 29 homers.
Two players Washington moved this season took more unexpected strides. Infielder Curtis Mead, who was traded to the Red Sox prior to the deadline, and Luis Garcia Jr., who was traded to the Yankees at the deadline, are the breakout examples. Mead enjoyed an impressive year in Washington, totaling a career-high 18 homers with an .852 OPS in 87 games with Washington. Garcia Jr. was magnificent for the Nationals, also setting a career high in homers (23) while posting a .560 slugging percentage.
Nats entering Sept. 4MLB rank
Home Runs
193
2nd
OPS
.754
3rd
SLG.4292nd
Runs
735
2nd
There are plenty of examples outside of Washington, too, including the Cardinals' Jordan Walker. Earlier in his MLB career, the 24-year-old outfielder hit the ball hard but too often on the ground, combining for a 47.6% ground-ball rate across parts of his first three seasons in the majors.
Last offseason, Walker went to Driveline, where the technology helped provide information that he and St. Louis hitting coach Brant Brown could use to shape his swing. The data showed that Walker's back hip collapsed, causing him to drift toward the ball. Brown identified another issue: Walker's elbow and barrel would get behind his torso, making it difficult for him to get his best swing off.
Using that information, Brown and Walker worked toward a solution. They implemented a slight dip in Walker's load, helping him produce better results in the air while still allowing him to get to the pull side when needed.
The shift in approach and setup, including standing taller at the plate, helped Walker ascend to stardom this year, hitting .289 and winning the Home Run Derby in July. His ground-ball rate has dropped to around 41%, while his average exit velocity has remained roughly in line with years past at 92 mph.
The results with both Washington and Walker show what can happen when the data and the communication of that information are aligned.
"Any success we're having this year is largely due to the talent, open-mindedness and work ethic of our players," Toboni said. "No single person has it all figured out, and that's a big part of what makes us go."
The 2026 Nats offense shows what can go right for a team that embraces data-driven coaching. But elsewhere in the DMV, the approach hasn't seen sustained success.
The modern hitting philosophy in baseball, heavily influenced by Driveline, has increasingly centered on a simple ideal: hit the ball in the air to the pull side, and do it with elite bat speed.
"Every qualified hitting coach understands the importance of moving the bat fast and getting the ball in the air to the pull side," said one National League executive.
The numbers explain the appeal. Since 2022, balls hit in the air to the pull side have produced a whopping .477 batting average and 1.694 slugging percentage.
"There's a huge emphasis on elevating the ball in the air to the pull side from a third-party standpoint," said Diamondbacks assistant general manager Mike Fitzgerald. Since 2023, Arizona's .747 OPS ranks fourth in baseball. "I think, objectively, that is where most slug exists. But, like, organizational philosophy has been, if you sell out to that, that's going to come at a cost. And so let's just make sure we understand what that cost is."
That cost is where the conversation becomes more complicated. There's nuance, Fitzgerald added. Pulling the ball in the air with authority produces undeniable results. But doing so requires the barrel to work farther out in front, which can sacrifice plate coverage. Selling out for the pull side can reap enormous rewards. The question is how many hitters can actually do it consistently without comproming other parts of their game.
"It's dumb," said first-year Orioles first baseman Pete Alonso, who is closing in on 300 career home runs in his eighth MLB season. "Organizations now are huge on fixed outcomes. Everyone wants a homer. But there are so many at-bats where doubles are great. Hits are great. Walks are great. Homers are just happy accidents. Why am I gonna just waste all of my at-bats trying to hit something I'm gonna do 1% of the time from all the pitches I see?"
The Orioles offer a case study in what can happen when that pursuit becomes an organizational philosophy.
In fact, Baltimore delved so deep into pull-side power in the air that one time, for example, a veteran player working his way back to the big leagues showed up to the minor-league ballpark with a batting tee, and it caught the coaching staff off guard.
"We haven't seen one of those in a while," one of the coaches said.
