Williams is likely to join the Sydney Roosters in 2013 after a short term, money making stint for the Panasonic Wild Knights. He is expected to earn $1.2 million for his time in Japan.
No deal has been signed with the Roosters, but according to reports he is also being offered $800,000 to return to the NRL.
Williams left Canterbury in 2008 and moved to Toulon RU in France. He has since left the French club, and has played for the Crusaders and Chiefs in the Super Rugby competition.