Manu became a Roosters stalwart across 181 games before joining Japanese rugby union outfit Toyota Verblitz following the conclusion of the 2024 NRL season.
The former rugby league Golden Boot winner had been due to link up with French rugby team Racing 92 from July ahead of the Top 14 season slated to begin in August.
But reports on Thursday suggested Manu was instead angling to return to either Australia or home country New Zealand on compassionate grounds.
NRL clubs have until June 30 to finalise their rosters for the ongoing season, leaving a window for the 28-year-old to sign a rugby league deal if a release from Racing 92 can be finalised promptly.
But Roosters coach Robinson had not heard from the utility back prior to Thursday's reports, leaving him doubtful of an NRL comeback with the Roosters this year.
"I had no idea about it at all, so that's the first thing. Joey, this is his home, it always has been," Robinson said.
"But I'm sure he's got a plan. If he's asked for a release, then he'd have a plan on what he wants to do, and that's not going to be us."
Robinson handed Manu his debut in 2016 and sculpted him into one of the NRL's most versatile players, equally damaging at centre and fullback and able to fill in as a five-eighth in a pinch.
Robinson said he would always be keen on the prospect of the 2018 and 2019 premiership winner returning to the Roosters.
"Naturally you would, but that's not our choice. Joey gets to make his choice," he said.
"He doesn't owe us anything. We've spent a lot of time together. There's obviously a professional relationship with the Roosters and also a lot of care for his family.
"I don't know if it's true, I've heard it reported. But until Joey tells me, then I won't be interested in why he doesn't want to go to France."
Robinson said it was bittersweet to drop struggling halfback Chad Townsend to take a chance on rookie Hugo Savala in the Roosters' clash with Brisbane on Friday night.
Towering local product Savala has played three games to date, all from the bench, but will partner five-eighth Sandon Smith as Easts hope to bounce back from a poor 1-4 start to the year.
"It's really sad on behalf of Chad, and then really excited for Hugo," Robinson said.
"You've got tough news on a guy that's tried so hard ... and then you get to give the guy that's been working really hard his first start as a half in Roosters colours."
