Last month, the Super League leaders announced they had signed the 21-year-old, claiming he had agreed a two-year deal.
But yesterday, as exclusively revealed in The Yorkshire Post, it was claimed the player had changed his mind and now wanted to stay with Huddersfield.
This has prompted Hull to issue a strongly-worded statement, claiming contracts have already been signed by Connor, whose Giants deal expires at the end of this season, and the player passed a medical last week.
“This contract is legally binding and states that the player has signed for Hull FC and will join the club from December 1, 2016 in preparation for the new season,” the statement said.
“If the contract is not fulfilled for any reason then the club will have to pursue legal proceedings for breach of that contract and for the inducement of that breach.
“The club have acted properly and professionally throughout all aspects of the process, working appropriately within the tight parameters of the game’s operational rules and with close guidance from the Rugby Football League.
“Any suggestion other than this by any other party is merely speculation and false conjecture.”
Hull KR have confirmed assistant coach Willie Poching will leave the club at the end of the season.
The 42-year-old former New Zealand and Samoa international, who has spent the last two years with the Robins, briefly took on the role of caretaker coach when Chris Chester left in February, but will not be part of the new coaching team for 2017.
Hull KR prop James Green will miss next week’s Hull derby through suspension.
Green was given a two-match ban for punching former team-mate Jordan Cox during his side’s 16-16 draw with Warrington.
Green, who was sent off for the grade C offence, was also fined £300 when he appeared in front of a RFL independent disciplinary tribunal in Leeds last night.
He will start his ban when Rovers host Huddersfield on Friday.
Rovers will have Ben Cockayne available for Friday after he was found not guilty of a grade B dangerous contact charge.
Wakefield prop Anthony England was given a two-match ban and a £300 fine after admitting a grade B shoulder charge on St Helens captain Jon Wilkin.
Wigan will be without front rower Lee Mossop for their home game against Wakefield on Friday after he was given a one-match ban for a trip on Glenn Stewart during his side’s 26-6 win over Catalans Dragons in Perpignan.
Leeds’s Brad Singleton was given a £300 fine after pleading guilty to grade A high tackle against Widnes, but he avoided a ban.