The Warriors and NBA are hitting back against one of their own.

The fan who pushed Kyle Lowry in Game 3 of the NBA Finals on Wednesday night wasn’t just any courtside fan, it was Warriors minority owner Mark Stevens.

On Thursday, the team and league slapped Stevens with a yearlong ban from all NBA games and Warriors team activities, in addition to a $500,000 fine.

Lowry dove out of bounds to save a loose ball in the fourth quarter and landed on fans in the courtside seats at Oracle Arena. Before the Raptors guard could get up, a man in a blue shirt reached over with his left hand and pushed Lowry’s left shoulder while delivering some choice words.

“It’s really not my jurisdiction,’’ Warriors coach Steve Kerr said. “But I will also personally apologize to Kyle and to the Raptors. That’s unacceptable.”

Stevens is a venture capitalist who joined the ownership group in 2013, according to Axios, which first identified him as the perpetrator.

“A team representative must be held to the highest possible standard and the conduct of Golden State Warriors investor Mark Stevens last night was beyond unacceptable and has no place in our league,” the NBA said in a statement Thursday.

Lowry, among others, had called for a lifetime ban, though the league did not go that far. It did little to slow down Lowry, who poured in 23 points to lead the Raptors to a 123-109 win.

On Thursday, Lowry continued his criticism of Stevens, calling his action “bullcrap’’ and saying the NBA could have done more.

“In that situation, I don’t think I could have handled it any better,’’ Lowry said. “I think more should be done. He’s not a good look for the ownership group that they have. And I know [owner] Joe Lacob. … The ownership that they have that I know, they’re unbelievable guys. But a guy like that, showing his true class, and he shouldn’t be a part of our league.”

LeBron James blasted Stevens on social media, calling for “swift action.”

Warriors star Stephen Curry saluted Lowry, saying he “handled it correctly.’’

“I don’t necessarily think it was a reflection of how we handle business here as a Warriors organization,’’ Curry said. “We have a high standard. And I know Mark is apologetic and whatnot, but we’ll handle that situation.’’

Draymond Green, known for being hot-headed at times, also said Lowry is the hero in this.

“I think you have to give Kyle a lot of credit,’’ Green said. “You’re playing in the NBA Finals, so your emotions are running high. It says a lot about his character.’’

Stevens apologized in a statement: “I take full responsibility for my actions last night at the NBA Finals and am embarrassed by what transpired. What I did was wrong and there is no excuse for it. Mr. Lowry deserves better, and I have reached out today in an attempt to directly apologize to him and other members of the Raptors and Warriors organizations.”

— Additional reporting by Marc Berman