Cooke quits Hull to join Rovers
Hull FC stand-off Paul Cooke has handed in his resignation at the KC Stadium and is expected to join Hull KR on a three-and-a-half year contract.
Cook, 26, is a lifelong Rovers fan who had been at Hull for nearly 10 years.
"I confirm that I have asked Hull FC to transfer my player registration to Hull KR and have notified the Rugby Football League accordingly," he said.
In a statement, Hull said: "This is now in the hands of our lawyers. We will make no further comment at this stage."
Earlier, Hull said an employment law specialist had confirmed they had a legally binding contract with Cooke, but he says he never signed the three-year deal they offered him in June.
"For some time I have been unhappy with a number of aspects of my contract with Hull FC and for that reason did not sign it," he said.
"After almost 10 years at the club, it is disappointing to leave in this way but all I can say is that I have enjoyed playing football for Hull FC and thank its thousands of fans for supporting me through the years.
"I am very happy with the contract arrangements that have been offered to me by Hull Kingston Rovers and now look forward to helping them maintain Super League status."
If Cooke's move goes through smoothly, he should make his Rovers debut against Huddersfield at Craven Park on Friday.
His next appearance for the club would then be against Hull FC at the Millennium Stadium on 5 May.