The 26-year-old joined Newcastle from Canberra in 2015 and was regarded as a consistent performer during his stint in the Hunter.
He made just one appearance for the club this season in their 32-28 defeat to St George Illawarra in Kogarah a month ago after a knee injury cruelled him earlier in the year.
“Sammy is happy with where he is at which is fine,” Brown said.
“We’d love him to be playing as we’ve got a shortage in that area but if you don’t want to play you shouldn’t play and I’ve always said that to him.
“Last year when he was fit and his mind was on the job he was one of our better players. The NRL is too hard a business if you don’t have a love for the game and do all the right things away from the field.
“He’s been through some difficult times and said his life away from here is what he is happy with.”
Mataora was one of 15 players off contract at season’s end with Brown indicating the club could be about to undergo one of the highest turnovers of a roster in the club’s history.
Peter Mata’utia heads the list of players facing an uncertain future alongside names that include prop Jack Stockwell and experienced veterans Anthony Tupou and Mickey Paea.
Luckless hooker Rory Kostjaysn is expected to retire due to a throat injury.
“We do have a lot of players off contract at this stage of the season so we do have a lot of work to do,” Brown said.
“It will never be the same again where we’ll have that many people off contract and the club will never have another bigger turnover than what we’ll have this year.
“Next year will be far harder to make the team with the recruits we’ve already signed and are hopeful of adding. Our depth and experience will change a lot.”
After announcing the signing of Tautau Moga on Tuesday, the club are set to add more recruits to the 2018 roster in the coming weeks.
However Brown stopped short of indicating Roosters utility Connor Watson was a guaranteed signing.
“He’s a work in progress. It is well documented we have spoken with Connor and he’s a player that we feel can certainly help our squad and he’s consistently making the Roosters who are a top-four team,” he said.
“We went for Jack Bird as we want a running six and we see Connor as that type of player. He carries the ball well but if he’s not to come then we will look at the next best option.
“He’s certainly a player that if the Roosters want to let him go or feel it’s right to let the kid go, we’d certainly be interested in him.”
Watson will take on the Knights on Friday night in the No.1 jersey vacated by the pectoral injury to regular fullback Michael Gordon.