Bobby Portis has no pretensions he will start this season at center over 21-year-old phenom Mitchell Robinson.

Portis, the 6-foot-11 big man who signed a two-year, $31 million deal with the Knicks earlier this month, has designs on a different goal — to be the leader of what he feels will be a top-notch bench.

“I don’t care about starting or coming off the bench,” Portis told The Post in a phone interview from Los Angeles on Friday. “I envision myself being a Sixth Man of the Year candidate. Last year I was in the running at the beginning of the season, playing well. That’s in the back of my mind for sure. Naysayers will say I’m crazy. I feel it’s going to come for me one day for sure. I play my role really well.”

As has been well-documented, the Knicks failed to land a star in free agency but instead used $70 million in cap space to form an extremely deep roster. The 24-year-old Portis, whose second contract year is a team option, says the Knicks will field as good a bench as there is in the NBA — outside of the Clippers.

Portis — who averaged 14.2 points, 8.1 rebounds and shot 39.3 percent from 3-point range last season with the Bulls and Wizards — is a natural power forward. But he will see most of his minutes at center because of the roster’s makeup.

“I think we’ll be a top-ranked [bench] after the Clippers with Lou [Williams] and Montrezl Harrell — that’s pretty strong. With our bench we have really good weapons in me, Marcus [Morris], Taj [Gibson], Allonzo Trier, Wayne Ellington. The list goes on.

“We have a quality rotation of guys in the league for a while now. That’s being slept on and not really talked about. People are living in the past with the Knicks. We’re not part of that. We have to create the now and present.”

During his Knicks meetings June 30 in L.A., Portis was told by brass Robinson was the starting center.

“Julius [Randle] and Mitchell will probably be starting power forward and center, but we have a lot of weapons coming off the bench that will be fun to watch,” Portis said. “I go out and play with a ton of passion and play the right way. In the amount of minutes, 20 to 26, I can affect the game in a lot of positive ways.”

The oddsmakers are not expecting much from the Knicks this season, after their free-agent dreams of landing a superstar or two — along the lines of Kevin Durant, Kawhi Leonard, Kyrie Irving and Kemba Walker — went up in smoke.

Though Knicks president Steve Mills and GM Scott Perry have declined to talk to the media since free agency began, Portis has been beating the team drum.

His summer workouts with a new conditioning man, Amoila Cesar, and new diet are putting Portis in position for a breakout season. He wants to be known for a lot more than the guy who punched out former Bulls teammate Nikola Mirotic in 2017.

The Wizards told Portis he needed to drop weight in his exit interview after playing the season at 261 pounds.

“I got real heavy last year,” said Portis, who will hold a basketball camp for the Bobby Portis Foundation from Aug. 9-11 in his hometown of Little Rock, Ark. “I’m honing in on getting down to 245, so I’ll be quicker on my feet.”

Part of his summer program included a 10-day no-sugar fast in June, even forcing him to change toothpaste. He dropped 4 pounds in the 10 days, still is on a low-carb diet and is at 248 pounds.

“It was really hard,” Portis said. “I couldn’t eat fruits. The 10th day I had some good French toast. It was really hard on me, but my body changed over the summer. I’m thrilled every Monday to do the weigh-in and every time it goes down.”

Portis said he’s also working on ball handling so he can push the pace in transition — an element coach David Fizdale talked about in their meeting.

“And I’m trying to maintain my shooting,” Portis said. “I shot the ball really well last season.”

So well he thought he was a lock to re-sign in Washington. Entering free agency, the Wizards had yet to hire a new GM to replace Ernie Grunfeld. According to an NBA source, there was turmoil in the Wizards front office that needed to be resolved before Tommy Sheppard could be named GM on July 19.

“I thought I was going to be a Wizard again,” Portis said. “It was really weird. They would go back and forth to wanting me, to not. They had a lot of things going on. It didn’t go the way I thought it would happen. Everything is a blessing.”

Portis heads to New York on Sept. 1 to find a place and begin informal scrimmages with new teammates. Despite his wheat-free life, Portis is looking forward to a New York bagel.

“I’m still going to have to try one,” he said.