The big name signing may spell the end of Copley's days at the Broncos.
Copley had been groomed to take over at centre from Hodges who drew the curtain on his glittering career after Brisbane's NRL grand final loss to North Queensland.
He is now expected to be on the way out, with utility back Lachlan Maranta another possible casualty.
It may become a straight swap with Copley moving to the Gold Coast who are suddenly down two centres.
Copley - who played just nine games this season - has already been linked with Parramatta and Newcastle.
In all, the injury-plagued Copley has played 72 games since his Broncos debut in 2009.
Broncos boss Paul White said signing Roberts as Hodges' replacement was a pleasant surprise.
"We certainly did not expect this opportunity," he said.
"The negotiations have certainly not been just about the contract value.
"James is obviously motivated to play for the Broncos for the benefit he will see both on and off the field.
"James is one of the most exciting young players in the NRL and we believe playing in the Broncos' system can help take his game to the next level."
Roberts - a 2016 Indigenous All Stars selection - became one of the league's hottest properties after scoring 16 tries in 24 games for the Titans this season.
South Sydney coach Michael Maguire and CEO John Lee met with Roberts on the weekend and saw him as an ideal replacement for Dylan Walker.
Roberts is a South Sydney junior and played 10 NRL games for the Rabbitohs in his 2011 debut year, before switching to Penrith for 2013, where he played six games.
He was eventually sacked by both clubs for disciplinary reasons.
Roberts' manager Jeremy Donovan believed his nephew looked forward to being taken under Bennett's wing.
"He has had the opportunity to make a decision on his playing career and where he believes he will thrive not just as a player, but as a person," Donovan said.
"James has had the opportunity to consider what club and culture best fits him and his family."
