Bradford are fighting to keep their assistant coach, Steve McNamara, the man Hull want to take over from John Kear who left on Monday after being told that his contract would not be renewed for next season.
Hull immediately asked the Bulls for permission to speak to their former player but Bradford remain keen to keep McNamara.
"We've spoken to Steve at length and made it very clear that we would like him to stay," said the Bulls' chief executive, Gareth Davies. "My expectation is that it will be a few days before we know one way or the other."
McNamara is Hull's first choice, although Salford's Karl Harrison and the Australians Chris Anderson and John Lang are other names being mentioned. Kear, could re-emerge at Wakefield, working alongside Tony Smith.
Hull still hope to have their new coach in place before Friday night's game against Leeds.
Wigan will travel to Salford in one of only two all-Super League ties in the fifth round of the Challenge Cup next month.
The tie of the round is at Knowsley Road, where St Helens will play Bradford.
Powergen Challenge Cup Fifth round draw: Salford v Wigan; Huddersfield v York; Widnes v Catalans Dragons; Leeds v Rochdale; Hull KR v Featherstone; Harlequins v Barrow; Warrington v Whitehaven; St Helens v Bradford. (Ties to be played on the weekend of 19-21 May).Reuse content