Widdop departed Kogarah in 2019 in order to return home to UK following struggles with homesickness, with the condition that he would not be able to return down under following his move to Warrington.
According to NRL.com, that stipulation is now lifted, with the 32-year-old free to link up with an Australian side as he looks to move back with his family - who are currently residing in Wollongong.
Warrington are understood to be happy to let go of their veteran half almost immediately, should they be able to land recently-released Raiders playmaker George Williams this season.
The Raiders managed to settle for a release that will see Williams return to England as he too was found to be unsettled and missing home.
Williams' departure has opened up a list spot for Canberra, who have seen Widdop as a suitable asset that could steer their form back in the right direction.
Widdop played a total of 196 NRL games between his stints with the Storm and Dragons, and has represented England on 29 occasions.
The Wigan Warriors pair will venture to Concord at season's end, with Hastings linked to an earlier move should the Greater Manchester club be able to land Williams' signature.
Williams is doubted to return to Wigan - the club that started his career - as Warrington look to have won the race for his services, per SARL.