The Red Sox didn’t win the pennant this year, but there’s still a Boston team out there in the 2016 World Series. It’s just that its members are playing in Cleveland, where Mike Napoli is manning first base and Andrew Miller is spitting bullets out of the pen for the AL champions, and in Chicago, where Anthony Rizzo, Jon Lester, David Ross, and John Lackey are key members of a 103-win club on a comeback mission. That’s no accident: The Red Sox of the late 2000s and early ’10s were a player development and acquisition juggernaut of outsize influence on today’s game, and nowhere is their legacy more deeply felt than in the World Series we’re all watching this week, with one Fenway alum after another propelling his team to victory.

Alongside current Cleveland skipper Terry Francona, who guided the Red Sox to their drought-breaking victory in the 2004 World Series and another title in 2007, the man most closely associated with that Boston operation is current Cubs president Theo Epstein, who presided over nearly a decade of baseball excellence in Boston as GM. While with the Red Sox, Epstein followed in the footsteps of Oakland GM Billy Beane and sabermetric pioneer Bill James, developing a reputation as one of the most prominent faces of baseball’s brave new world of analytics. That was well-deserved — Epstein understands the quant side of baseball as well as anyone — but it missed an additional, critical point: Few baseball executives give as much of a shit about the human side of the game as Epstein. That elevation of the personal, as much as anything he’s ever done with a spreadsheet, defined the Red Sox culture that’s still on display in Cleveland and Chicago this week.

Throughout his time in Boston, Epstein made it a priority to get to know his players, both before and after acquisition, learning about their fears, their families, and their lives before the game and supporting, to the degree that he could, their development as human beings and not just as as baseball players. “He definitely has a huge analytics background,” said Lackey, “but he’s a little more personable, I guess, than some of the nerds upstairs.” Epstein’s healthy appreciation for the gray areas of life, combined with his laser-like focus on even the smallest details of personal relationships, color all aspects of the organizations he runs, and has fostered in those who’ve worked and played for him not only an unusual loyalty to their boss, but a sense of shared commitment to one another.

Consider this: Three of Epstein’s top lieutenants in Boston — Jed Hoyer, Jason McLeod, and Jared Porter — have joined him as senior execs in Chicago, and at least one (McLeod) has turned down consideration for promotion elsewhere to stay on Epstein’s team. It’s not surprising. “Theo is very inclusive in terms of ideas,” said Peter Gammons, the Hall of Fame sportswriter and Boston native. “He’ll listen to everybody. He sees everything, and is aware of everything, but delegates so much authority.” That delegation has enabled talented deputies to stay with Epstein rather than leave to be their own boss somewhere else.

The relationships have lasted for players, too. A day before facing Napoli and Miller in Game 5 of the World Series, Lester spoke glowingly of his time with the Red Sox. “There’s always that relationship with those guys,” he told me this week, with an intensity that carried the phrase beyond its normal strength. “There’s always that bond. With Nap, I played just a season and a half with him, and I consider him one of my brothers — one of those guys that are more than just baseball friends. He’s a lifer for me.” Napoli, asked about Lester moments later, gave the same answer almost word for word. Friendships that last beyond baseball aren’t unique to Red Sox alums, but they have been remarkably common among them in the past decade and a half.

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Those ties have aided recruiting: Epstein leaned heavily on his relationships with Lester, Lackey, and Ross (in addition to the Cubs’ piles of cash) to convince them to join him in Chicago, joking that he’d have soaked himself in deer urine if it’d attract Lester, an avid hunter. They’ve translated to success on the field, too. Gammons recalled a key moment from 2013, the year Boston last won it all:

That October, Andrew Miller — then 28 years old, and nowhere near the star he is today — was left off the Sox’s postseason roster because of a broken foot, and feeling despondent. He approached Gammons — a friend through their shared North Carolina connection — and opened up. “You know, I’m not sure I should stay here,” he said, “because I’m not sure I’m contributing to the team, and I’m not sure I belong.”

After a few more words, Miller left to get in his work in the outfield, and Ben Cherington — a product of Boston’s front office who’d succeeded Epstein as Boston GM after Epstein joined the Cubs in 2011 — came down to shoot the shit with Gammons, who mentioned how down the Sox’s young reliever was feeling. “And when I look up 15 minutes later,” Gammons remembered this week, “Ben is sitting in the stands with Andrew Miller.” After they’d talked, Miller came back to Gammons with the news: Cherington had sat him down and set him straight. “Andrew,” Cherington had said, “the Red Sox wouldn’t be here right now if it weren’t for you.”

Now, you’d be projecting a little bit if you connected that story too closely to Miller’s emergence on the national stage, which happened right around the same time the next season, his first truly dominant campaign. But Gammons did, and he’s been at this a lot longer than most of us. And asked about that moment, Miller remembered it instantly. The 2013 Red Sox are now three years a memory, but the relationships forged and lessons learned during that era of Boston baseball have lasted.

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For the former Red Sox, then, the Boston culture they shared has added a unique dimension to what is already a surreal experience at Wrigley Field and in Cleveland this week. Ryan Dempster, who pitched for that championship Boston squad in 2013 and is now a front-office adviser for the Cubs, took care to emphasize the degree to which a World Series heightens everything a player is experiencing. “You learn what this kind of emotion feels like when you’re in [a World Series] for the first time,” he said this week. “But even then, trying to understand and control those emotions sometimes can be tough.” Lester, who won two titles in Boston, most recently with Dempster in 2013, echoed that sentiment. “I don’t think the feeling ever changes [when you get here],” he said. “I think it’s always the same, and always unique. It’s something that you can’t ever prepare for. This is what you play for.”

That feeling, and beating your buddies. This time around, part of the joy for Lester is getting to play against his friends from the old days. “As good of a relationship as I have with those guys, that doesn’t mean I don’t want to beat them,” he said. “And I imagine the same holds true for them.” No kidding.

All around the league, there are players — young, old, and everywhere in between — who came up through or out of the Boston organization during its run of dominance, and bear with them rings and friendships that will last forever. Sure, for some the connections have faded faster — when I asked Rizzo, who was traded from Boston as a minor leaguer in the winter of 2011, who he was still in touch with from those days, he thought for a good while before finally naming only a few coaches. For others, however, that time still defines them. “I talk to those guys all the time,” Napoli said, before doing his best to take a hammer to them in Chicago. “I’d do anything for them. We still have that bond, and it’s something that’ll never change.”

The era that brought them together is over now, even as a respected baseball man in Dave Dombrowski runs the show in Beantown, but its legacy is very much alive in the players who were there when the city ran the baseball world. They were selected for Boston’s roster, in large part, for their ability to produce value on the field in a way that the newfangled numbers understood. But since they’ve left, what’s lasted — besides the championship rings — has been the friendships they built with each other, and the culture of respect, intensity, and brotherhood that they cultivated there, and now carry onto the field against each other on baseball’s biggest stage.