Nuuausala, who played 153 games for the Roosters between 2007 and 2014, was released by English Super League club Wigan last week citing homesickness.
The 31 year old Nuuausala, who was part of the Roosters' premiership-winning team in 2013, toured Australia with Wigan earlier this month and decided to stay behind, in a bid to make a return to the NRL after last playing for Canberra in 2016.
He will start training with the Roosters immediately and will add strength to Trent Robinson's bench, which could also possibly include Jared Waerea- Hargreaves and Zane Tetevano.
"It's great to welcome Frank-Paul Nuuausala back home to the Roosters," Robinson said.
"Frank's a good man and an experienced campaigner who still has a lot of good footy in him.
"He adds depth to our forwards and we're all pleased to see him back in Roosters colours."