Leeds Rhinos signed half back Robert Lui on loan during the 2019 Betfred Super League season and agreed a two year contract with the 29-year-old from 2020.
The Rhinos have paid an undisclosed loan fee to the Red Devils with Tongan international Tui Lolohea moving in the opposite direction.
He made a winning debut for the Rhinos against Catalans Dragons at Emerald Headingley.
Lui has spent four seasons at the AJ Bell Stadium making over 100 appearances for the Red Devils and scoring 31 tries in the process. He has previously played in the NRL with Wests Tigers and North Queensland Cowboys having made his debut as a teenager in the NRL.