The Dragons tabled an offer to Cuthbertson and his manager, Andrew Purcell, more than a month ago but a deal was never finalised.
''We let the original deadline go and [the Dragons] never came back to us,'' Purcell said. ''It's highly unlikely he'll remain at the club, considering the amount of signings they've had since then.''
Newcastle have shown interest in the former Manly and Sharks forward but they are yet to put forward a deal to secure his services.
It is believed the Roosters, who have already signed fellow Dragons Jack Bosden and Peni Tagive, as well as the Eels are keen to lure Cuthbertson to their clubs for next season.
His desire is to remain in the NRL, but the money on offer overseas in the English Super League may prove too attractive to turn down. Leeds, Hull KR and St Helens have all begun talks with Purcell to entice the Dragon to Britain next year.
