Kyrie Irving explains to Rachel Nichols why he decided to call LeBron James and apologize to him. (0:55)

Kyrie Irving said his phone call to LeBron James earlier this year to apologize was necessary in part because he "didn't address the situation" while the two of them were teammates in Cleveland.

"Well, I think that, you know, it takes a very, very strong individual to replay a lot of the experiences that you've had," Irving told ESPN's Rachel Nichols. "A lot of anger that you've had built up, where you didn't address the situation and you allowed it to fester. And then it was just combustion.

"It came out and it just ... you realize, like, 'Hey, man, I didn't have to deal with that the same way I dealt with that. I didn't have to go about it that same way.' Now, mind you, I have no regrets in terms of any decision I made, going about my individual journey and what I want and foresee for my career.

"But for me, it's just ... apologizing, yeah, that was a step for me, just to move forward in my life."

When asked about his phone call at All-Star Weekend's media day Saturday in Charlotte, North Carolina, Irving had far less to say about it.

"That's none of your business," Irving said.

The Celtics point guard first revealed that he called James in a postgame scrum after the Celtics beat the Toronto Raptors last month in Boston. That was just one of several twists and turns involving Irving -- including the ongoing drama surrounding Boston's long-term pursuit of Anthony Davis and Irving's declaration in New York on Feb. 1 that he's going to "do what's best for his career" when he hits free agency, as opposed to his prior stated commitment to re-sign with the Celtics when he can opt out of the final year of his deal July 1.

Irving and James played together in Cleveland for three seasons, reaching three straight NBA Finals and winning the 2016 NBA title when Irving hit the game-winning shot in Game 7 of the Finals to complete a comeback from down 3-1 against the Golden State Warriors.

A year later, though, after Golden State won the 2017 rematch in five games, Irving requested a trade. Eventually, Cleveland acquiesced, sending him to the Celtics for Isaiah Thomas, Jae Crowder, Ante Zizic and the rights to the Brooklyn Nets' 2018 first-round pick, which eventually became Collin Sexton.

James would go on to join the Los Angeles Lakers as a free agent last summer, while Cleveland wound up trading both Crowder and Thomas at last season's trade deadline to help bolster the team for the playoffs -- the Cavs wound up making a fourth straight NBA Finals and once again lost to Golden State.

Irving spent last season's playoffs sidelined following knee surgery, as did Gordon Hayward after suffering a gruesome leg and ankle injury in the season's opening game in Cleveland. The return of both to the lineup this season created a fight for minutes and ongoing tension in the locker room -- particularly among the team's younger players.

Those have been just some of the issues that have plagued Boston this season as the Celtics -- even though Irving has played the best basketball of his career -- have disappointed. The Celtics begin the stretch run in fourth place in the Eastern Conference.

"It's been a trying year for us," Irving told Nichols. "We basically have a bunch of young men in our locker room who feel like they're capable of doing a lot more than they're doing. And that's OK, but there's a maturing that you have to have. There's a professionalism that you have to showcase every single day, and that's what the great ones do.

"I initially didn't play the minutes I wanted to play. I'm 26 years old, heading into my prime, like, why do I have to wait for anybody? [Terry Rozier] played in the playoffs. He did extremely well. Coming back, that's a natural competition that me and him have.

"It is what it is. No one wants to say it, but I will. You know, [Jaylen Brown, Jayson Tatum], all these guys, it's part of their growth. When you have winning in mind, you've gotta understand that. You gotta do what it takes, but you gotta understand your teammates."

Boston will return to the court Thursday in Milwaukee, where the Celtics will face the East-leading Bucks.