Cam Thomas has plenty to prove to himself and the Nets in his contract year

This is a contract year for Cam Thomas. A huge year.

And he insists he isn’t changing who he is as a player. But he’s clearly still growing into exactly who that will be.

After failing to reach an agreement on a long-term extension with the Nets — settling for the one-year qualifying offer that suggests a possible departure from Brooklyn — Thomas has looked like a man on a mission so far this training camp and preseason.

But what exactly will that mission be?

“Cam, he has the ability to be one of those guys, young, still trying to find his way,” Hall of Fame ex-Net Vince Carter told The Post. “But this is the big year for him.”

For good reason.

Thomas was a restricted free agent this summer and rejected both of Brooklyn’s reported offers, a two-year, $30 million deal and a $9.5 million deal with incentives. Ultimately, he settled for the one-year qualifying offer of $5.99 million. It gave him a no-trade clause and, perhaps more importantly, unrestricted free agency.

But with freedom of choice comes responsibility. Thomas has to prove that he can not only score — that has never been in doubt — but also stay healthy, defend and be a playmaker.

After Thomas played just 25 games last season due to hamstring injuries, he lost weight this summer and came to camp in better shape.

As for guarding and passing, that’s a different matter.

While Thomas joins Michael Porter Jr. adds as the best scorers on the roster, they are equally porous on the other side. Thomas’ lackluster defense cost them the loss on Friday, when he completely lost Collin Gillespie on his buzzer-beating 3 to end the half.

“NBA games are about the details. We gave up three points at the end of the second quarter. It would have been a 15-point game, but instead it was 12. Then we gave up another three points at the end of the third quarter. That’s six points,” said head coach Jordi Fernandez. “I want the boys to be focused not just at the end, but throughout the entire match.”

In terms of his play, Thomas looks more focused and mature. Of note is the fact that he will be in Sunday’s match against Phoenix in Macao, China, averaging five assists for the team.

Averaging just 1.8 for his career a year ago, his 3.8 last season showed growth. And his 5.8 in March was impressive, handing out a career-high ten in his last game in Chicago.

He expects, after six Friday vs. the Suns, to be more of a playmaker this season?

“No, I’m just playing my game,” Thomas said. “Teams are going to double me, so that’s going to lead to assists. If the guys make the shots, that’s going to lead to assists. So I’m just going to play my game, and if that requires the assists, then that’s fine.”

“But I’m still a goalscorer at heart. It also adds that playmaking aspect, being able to make the right play and hold the defence.” [honest]. So I’m just going to read the game. Some games it might be a lot of assists, and most of the game is about a lot of points. It’s just about reading the game and taking what the defense gives me.”

But Thomas is figuring out how to use his gravity to create looks for others. It will be a valuable lesson for the Nets and their young guard.

“Yes, Jordi and I always talk about it, we always have conversations about it,” Thomas said. “Jordi also understands very well who I am as a player. He knows that I am a goalscorer and he knows how I play.”

“But it’s also the fine line of being aggressive, creating your own shot and then getting different shots from the guys. We always have that dialogue, and it’s great. This year we have a better understanding. He understands me better, and I understand what he wants better. So that’s just going to lead to great things for us as a unit. So it’s definitely on the rise.”