WALTHAM, Mass. — As his Celtic teammates looked forward to a rare Friday night off in New York City, Jonas Jerebko put on a suit and headed to Wall Street.

The seven-year NBA veteran had a job to do — promoting the emerging esports industry and his Renegades esports franchise during a four-minute hit on the financial news network CNBC.

“I was a little nervous — not going to lie,” he said prior to Tuesday’s practice. “But it was great for me to get out of my comfort zone and try something new.”

This summer, Jerebko decided to put his love of video games and his experience in professional sports to use with an investment in what Forbes Magazine recently estimated is an industry with $900 million in annual revenue. In esports, teams of gamers compete in tournaments in front of thousands of live spectators at marquee events, and up to hundreds of thousands of followers during online and cable broadcasts.

“I think it’s a sport of the future,” Jerebko said. “It’s not just the future, it’s now if you look at how many people who watch.”

But does someone who was drafted to the premier basketball league in the world, and runs the court with some of the greatest athletes on the planet, really consider competitive gaming a sport?

“I say esports is definitely a sport,” he assured. “I’ve seen how much time they’ve put in. If you play video games, it’s not like 40 percent are going to turn professional. It’s that one percent who are committed, and put in the work, and put in the training. It takes a lot to become one of that one percent.

“I, obviously, know what it takes to become a professional athlete. In many of those games it’s a team game. I am trying to implement that into that world. It’s new to 90 percent of the population. But I think the bigger it gets the more people will see it’s pretty crazy and something real.”

Jerebko’s passionate defense of esports in the face of a skeptic is similar to the way he’s felt he’s had to justify his own game. A second-round pick out of Sweden in 2009, Jerebko made 73 starts as a rookie with the Detroit Pistons before an Achilles tear cost him the entire next season. From there, he started only 15 more games over parts of four seasons before being sent to the Celtics at the 2015 trade deadline.

He quickly found a renewed purpose and role under Celtics coach Brad Stevens during the team’s surprise playoff push, and re-signed in Boston that summer. But he again found himself drifting toward the back of the rotation at times last year as the Celtics vied for a top-four seed in the Eastern Conference.

“It’s the story of my career,” he said. “But it’s fine. I have no problem with doing it over, and over, and over again. I prove people wrong.

“I am used to going to media day and nobody really wants to ask questions. So it’s nothing new to me. I’m not complaining. I know how it goes. New guys come in, new guys get signed, and there’s all the hype. I don’t care. I do things myself. I help the team.”

By the end of last year’s first-round playoff series, he was Boston’s starting power forward as the Celts battled back from a 2-0 deficit with two home victories, before ultimately falling to the Atlanta Hawks in six.

“I am happy I got a chance to prove to everybody, once again, that I can play basketball,” he said.

In Saturday’s exhibition game at Madison Square Garden, he was the first frontcourt player off the bench against the New York Knicks. He was Boston’s leading rebounder with seven boards in Monday’s 120-99 preseason blowout of the Brooklyn Nets.

"We know what Jonas can do well,” Stevens said last week. “At the end of the day, we need Jonas to space the floor for us and be a versatile defender."

The emergence of rookie Jaylen Brown, and expected return of big man Kelly Olynyk (shoulder surgery) early in the regular season, could once again force him to fight for playing time. But the player who has so often seemed the odd man out, only to battle his way back in, is looking forward to doing it again with this team’s potential this season.

[The Pistons] "were always going in a different direction, and I always worked my way into the rotation there, too,” he said. “I like it here. That’s why I came back. I like being around the same teammates. I like being around the same coaching staff. I like consistency.

“You are not going to be a great team by, all of a sudden, getting a bunch of new guys on a team and then win a championship. You’ve got to build toward it for a few years.”

— Scott Souza covers the Celtics for The Providence Journal and other GateHouse New England newspapers.