The Roosters are all but resigned to losing Manu at the end of this season, with the 27-year-old having told the club he intends to make a move to French rugby.
Manu's value to the Roosters was underlined in Las Vegas, scoring an intercept try in Sunday's win over Brisbane and producing the play of the night with a no-look flick pass for Fetalaiga Pauga to score another.
Manu said after the match he was still "sorting things out" for 2025, but he was "most probably" leaving the Roosters to pursue a new career path in union.
"I just love the challenge of being uncomfortable," Manu said.
"I really feel like that's where you grow as a person and player, being challenged.
"It's not that I'm not being challenged here. But it's been a while since I've been here. I've been rusted into the spot for a while.
"But learning a whole new game and it's just something different and also experience as well."
The Roosters have been hopeful Manu will one day return to the club, in the same way Sonny Bill Williams did in 2020 after leaving for rugby union at the end of 2014.
Manu said that remained his plan, and he could never see himself playing against the Tricolours.
"I hope I get to finish my career here or get a few more years here," Manu said.
"I came here when I was 16. So to give back to the club, the fans, the members and all that, would be special.
"They kick-started my career and hopefully I get a few more years in."
Manu only played in the NRL's historic Las Vegas double-header after flying out of Sydney late following the birth of his first child Laylia last Saturday.
Had Manu's wife Ty given birth a day later, the Roosters had already decided Manu would remain at home.
Manu said there had been no consideration to advancing the birth, and he was prepared to miss the season opener if Laylia did not arrive in time.
"It was her having a baby. I just wanted to have her experience, and she wanted it naturally," Manu said.
"The main thing was for her to be as comfortable as she could be. I'm glad I didn't miss the birth. It's the best thing that's happened to me.
"It was tough. I honestly thought I wasn't going to come at one stage.
"Even when she came, I was like I will stay and look after baby and my wife. And then 'Robbo' forced me to get on that plane ... She was really supportive as well."
