The former Swans skipper is understood to be seriously considering trying to find a way out of the final year of his contract at the Swans to join the fight game.
The premiership winning forward has endured a controversy-filled year in the harbour city with his volatile temper and personal life regularly coming under scrutiny.
And the hardman appears keen to take out his frustration with his fists.
But Roos said he was unaware of Hall's keenness to quit the club.
"I would have thought if he was thinking about doing it he would have let us know," Roos told AAP from Port Douglas.
"This time of year everyone is away and doing different things and I have not really spoken to him about it.
"It is the first I have heard about it.
"I am probably not able to make too much comment about it because I don't know what is going on."
Hall is expected to spend a few weeks training with boxer Danny Green in Perth in the coming weeks.
Green is trying to entice Hall into boxing and said he had noted the footballer's enthusiasm to have a proper crack at the sport.
"I sense the excitement in his body language," he said.
"He still has a year to run on his (AFL) contract and he has to work out if it is worth his while."
Green admitted the prospect of having to pay the Swans compensation for breaking his contract could be a deterrent for Hall putting on the gloves.
"We are professionals and we know that and we are going to do everything by the book," Green said.
"I just want what is best for Barry."
Hall, who is 32 in February, was a quality boxer at junior level before deciding to focus on a career in the AFL.
The prospect of Hall combining football and boxing is unlikely.
He has said in the past that if he moved into boxing he would want to pursue it with all his energy, and the Swans wouldn't be keen for their star player having such a distraction.
Roos said he would be back in Sydney on Monday and expected Hall to report to pre-season training next month.
