The England forward, 29, was released by Wigan in February and had surgery on a hip injury which ruled him out of the 2021 Super League season.
He had joined Wigan in 2020 on a three-year contract after eight years at NRL side South Sydney Rabbitohs.
His twin Tom still plays for the Rabbitohs.
George made 149 NRL appearances for the Rabbitohs, winning the Premiership in 2014, where he played alongside Tom and his other brothers Sam and Luke, who have both since retired.