Knicks guard Frank Ntilikina controls the ball in the first half...

Knicks guard Frank Ntilikina controls the ball in the first half against the Nuggets at Madison Square Garden on March 22, 2019. Credit: Jim McIsaac

GREENBURGH, N.Y. — Frank Ntilikina’s long, difficult season is officially over.

After re-examining the second-year guard, the Knicks’ medical staff recommended that he miss the remainder of the season because of a groin injury, the team announced Friday.

“I’ve got to stay positive to what is happening,” Ntilikina told reporters at the Knicks’ practice facility. “As a player, you always want to play and be on the court and try to improve and try to play, especially with my teammates. It’s frustrating, but it’s for my health. I know it’s the right decision to make right now.”

Ntilikina originally injured his groin in late January and missed 24 games. He returned to action March 22 but aggravated the injury two days later and hasn’t played since.

The No. 8 overall pick in 2017 added nearly 15 pounds of muscle to his 6-6 frame over the summer and had hoped to improve in his sophomore season.

That didn’t happen, but injuries aren’t the only thing that has been disappointing about his year.

Ntilikina is one of the Knicks’ best defensive players but has struggled offensively. He averaged 5.7 points and 2.8 assists in 43 games, shooting 33.7 percent from the field and 28.7 percent from beyond the three-point line.

Ntilikina, who started the first 14 games, had only two more starts after Nov. 11. Before his injury, the low point came when coach David Fizdale benched him for three straight games in December. Ntilikina initially came back strong from the benching, then returned to his previous struggles.

“Physically, he was totally prepared for this year,” Fizdale said Friday. “That’s why I felt totally comfortable putting him on different people. He really put a lot into his body this summer. This kid, I feel really bad for him. He’s one of our hardest workers.”

Ntilikina initially was drafted as a point guard, but under Fizdale, he has spent more time playing off the ball. Then the Knicks acquired point guard Dennis Smith Jr. in the Kristaps Porzingis trade.

Asked if Ntilikina remains a part of the Knicks’ rebuilding plans, Fizdale said, “He’s still on our roster, isn’t he?”

Fizdale often has praised Ntilikina’s versatility. “I don’t see a position,” he said. “That’s what I keep stressing with Frank. Frank does everything for me. That’s why he’s so important. He can play point guard, two-guard and three. And he can guard multiple positions, and we just don’t have a lot of those on this team.”

But Ntilikina’s versatility often has translated into a lack of a defined role.

For now, he is trying to concentrate on the positive.

Ntilikina said of his season: “I think I still grew a lot as a player and a person, especially in my second season in the NBA. Of course it’s frustrating to not have played as many games as I wanted to. But I still got better.”

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