BOSTON — Ask Jon Lester how much Anthony Rizzo has matured since the two were in the Boston Red Sox organization together, and Lester doesn’t hesitate.

“He hasn’t.”

Lester is joking, of course, but there’s still a kid-like aspect to Rizzo, who returns to Boston Friday to play against the organization that drafted him — this time as a three-time All-Star and a world champion.

“His reputation with every scout, every player-development guy with the Red Sox was incredible,” Cubs general manager Jed Hoyer said recently. “When we traded for him in San Diego, I got a number of texts from people with the Red Sox, in player development, it was unbelievable. Everyone loved him and hated to see him go and felt like this guy wasn’t going to miss.”

Hoyer knows Rizzo’s journey as well as anyone in baseball. As a member of the Red Sox’s front office in 2007, he was involved in drafting him, then as general manager of the Padres he traded for him, and then did it again when he joined the Cubs before the 2012 season.

“He was a person from Day 1 you could tell he could be a leader,” Hoyer said. “When building a championship team you need those guys.”

When Rizzo was drafted, the Red Sox already were a championship-caliber organization. They had won the World Series in 2004 and then did it again months after Rizzo came aboard. There was a sense that just making it to the big leagues wasn’t enough — you had to be ready to win right away on the biggest stage.

“The debate is, ‘Do you go to college or do you go to the pros, right?’” Rizzo asked. “I’m biased because from ages 17 to 21, I was shaped and molded by such great professionals in the Red Sox organization. The way that organization was run was first-class and taught me a lot about everything — baseball, off the field, how to handle yourself. Those years were the most important. You can go down so many directions as a player and a person.”

As Rizzo was maturing as a player, he was forced to mature even quicker as a human being. Almost a year after being drafted, he was diagnosed with Hodgkin’s lymphoma, and then baseball took a back seat. The Red Sox were there for him well before he was a star in the league.

“They helped me so much,” Rizzo said. “They paid for all my bills; saved me debt and my family stress. They treated me like I was in the big leagues and I was just a minor leaguer trying to find my way.”

Between being groomed in the spotlight of the Red Sox organization and his illness, Rizzo was ready for just about anything — even though he didn’t realize it at the time.

“When you’re going through something, it’s the worst thing in the world,” he said. “You feel like you are never going to get out of it. But that’s when you learn, it’s learning. Even cancer is a learning experience. I had something more severe and life-threatening and I learned from it. Without that, I can’t do this.”

“This” is playing baseball at the highest level while giving back. The Rizzo Family Foundation is constantly working in the community, both in Florida and in Chicago, raising money for the less privileged. Surviving cancer gave Rizzo perspective, and perhaps it did something to his game on the field as well.

“He is fearless,” Cubs manager Joe Maddon said. “He doesn’t worry about minutia. He doesn’t worry about superficial nonsense … He does everything the right way, and part of that is the fearlessness component that you’re seeing.”

Maddon referenced jumping on the wall to catch a ball or playing bunt defense in the hitter’s face as examples of that fearless approach to baseball.

“It’s a hard thing to connect [the dots on], but I know what Maddon is talking about,” Hoyer said. “He showed it when he took on the Reds’ bench [in 2014], he shows it when he makes major changes to his swing and he’s fearless on the field.”

When Rizzo joined the Cubs in 2012, the organization was “upside down,” but he’s actually grateful for it; it allowed him to mature as a player without the pressure of expectations.

“I came up in ’12 and ’13 and the team wasn’t good,” Rizzo said. “If I came up now and had the year I had in 2013, I’m a platoon player. The faith they showed just running me out there is big.”

Rizzo hit .233 in 2013, including just .189 against left-handed pitching. He rebounded in 2014 — and has been an All-Star since. He hit .292 with 32 home runs and 109 RBIs in 2016 when the Cubs won the a World Series, and he is heating up again. Rizzo has four homers in his past six games heading into the three-game series in Boston.

“He’s very cerebral about the game,” Maddon said of Rizzo’s development. “He nitpicks the game mentally. He comes in with a lot of good thoughts — as many good thoughts as any player I’ve had, on any team that I’ve been with.”

Despite his growth as a player, Rizzo still hasn’t completely matured — from playing the “Rocky” theme in the clubhouse during the Cubs’ playoff run to admitting he was nervous he would make a mistake in Game 7 of the World Series.

“He’s in there pushing Lester’s kids around in a laundry basket,” Maddon recalled before a recent game. “He’s a big kid.”

He’s a big kid who survived cancer, navigated being traded twice and answered the challenge of being asked to be the face of a team desperate for a championship.

Lester has had an up-close view of both the Boston Rizzo and Chicago Rizzo. He met him not long after Rizzo endured his first chemotherapy treatment, so he saw him at his worst. Now he gets to see him at his best.

“Now he’s an MVP candidate, All-Star, Gold Glove first baseman and a really good guy in the community,” Lester said. “I can speak even from 2015 until now how much he’s matured and grown up.

“He’s taken on more. He should. He’s one of the faces of the franchise here.”

As for the franchise that drafted him, Rizzo has good memories despite dealing with his illness there. He thinks Red Sox fans can appreciate what he’s been through.

“I’m grateful,” he said. “Red Sox fans, I think, would say they were rooting for the Cubs in the World Series. … I usually hear ‘Hey, we loved having you here.’ I’m lucky to go from one storied franchise to another.”