Her job is using numbers to give the Astros an edge. But this baseball exec grew up in Philly.

HOUSTON — As a freshman at Germantown Friends, Sarah Gelles read the book Moneyball, about how analytics transformed baseball, and everything changed for her, too.

“It turned me on to this being a career option,” she said. This is a job as a baseball operations executive. At 34, Gelles is director of research and development for the Astros and one of the highest-ranking women in baseball operations.

But Gelles grew up in a family of Phillies fans with season tickets, first at the Vet, then at Citizens Bank Park.

“Growing up in the city of Philadelphia, it’s why I became a huge baseball fan,” said Gelles, whose favorite Phil growing up was Bobby Abreu. (”I was very much on the .400 OBP train,” she said, referring to the baseball statistic that takes into consideration how many times a player reaches base per plate appearance.)

Gelles talked her way into an unpaid baseball operations internship with the Phillies the summer before she started college, and found herself working the Major League Baseball draft.

“It was really just an opportunity to prove to myself that this was something I wanted to do,” said Gelles, whose father is a retired Inquirer reporter and columnist.

Working for the Phillies solidified Gelles’ ambitions. At Amherst College, she studied law, jurisprudence, and social thought, but made use of the school’s strong baseball network, and interned with the Pittsburgh Pirates’ research and development team. After graduation, she joined Major League Baseball, interning in the commissioner’s office on labor relations.

“But I missed the club side, trying to win a championship, which is what we’re doing here,” said Gelles. So she jumped to the Baltimore Orioles, where she started the team’s analytics department as an intern in 2011.

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The Pirates had been ahead of the curve on the research and development side, but the Orioles didn’t have that infrastructure when Gelles joined.

She saw an opportunity: Gelles taught herself SQL Server, a high-end system for databases, pitching to the higher-ups a $10,000 investment that would pay dividends. She hired some “very overqualified interns” and they built their first database.

“I think we prided ourselves with a relatively small staff on really being able to find competitive advantages with using data and analytics,” Gelles said.

Modern baseball is increasingly data-driven, using subjective measures, like scouting reports, and objective figures, like wins or hits, to help make decisions small and large. It affects scouting, player development — an entire organization.

The Orioles made Gelles a full-time employee in 2012. She worked in R&D, but also became the Orioles’ point person for Major League Baseball, working with roster management, rules, and collective bargaining agreement compliance. Eventually, she was promoted to director of analytics and MLB contracts.

Gelles isn’t a limelight person — she said her quick rise in baseball “only worked because of the era we were in,” she said. “Clubs are further along in the development cycle now.”

But Gelles has good instincts, is smart and personable, and has continued to ascend.

In 2018, after O’s manager Buck Showalter and general manager Dan Duquette were fired after a 118-season loss, the Astros, who had won their first World Series the year before, reached out to Gelles.

“I didn’t know anyone in Houston; they obviously have a reputation” for winning, Gelles said. “It was an exciting opportunity to go from somewhere where we had to do what we could with a much smaller staff to a place that proudly invested in R&D.”

It’s been quite a run in Houston, with the team making the playoffs consistently for several years running.

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Gelles often finds herself the only woman in the room, but works for an organization she says values her opinion. The Astros “believe in creating an inclusive culture. I’m proud that my team in R&D includes three awesome women” among its 16 members.

Upping the number of women in her field is something Gelles said she is passionate about. With the Astros’ support, she organized the first Women in Sports Data Symposium and Hackathon that was attended by hundreds of women.

But these days, the World Series is at the top of her mind.

And though she grew up in West Philadelphia, then Chestnut Hill, Gelles’ loyalties are clear.

“As soon as you start working for a team, I think it’s a lot easier to give that up than people would expect,” she said. “I would say my parents are much more conflicted than I am.”

Jeff Gelles and Sharon Gornstein, who still live in Philadelphia, are attending all the games in Houston.

“I don’t think my mother ever expected an Astros-Phillies matchup,” Sarah Gelles said. “She insists she’s rooting for the Astros, but I don’t know deep down how honest she’s being.”

This is probably the only part of the season where Gelles feels like a fan. This deep into the postseason, the outcome rests on the players and the coaching staff; though analytics do inform in-game decisions, those choices are made by folks on the field, using tools from Gelles’ team.

It’s not a quiet time of the year for her, juggling the playoffs with prep for the offseason and 2023, but “once the game starts, there’s nothing more for my team to do,” said Gelles.

And though the Phillies seemed to come from nowhere, she’s not taking the team for granted.

“Wild card teams can have a really good stretch,” said Gelles. “The Phillies are a fantastic team that legitimately could beat us over a seven-game series. We have our work cut out for us.”