Cardiff striker Ross McCormack has handed in a transfer request as he looks to push through a move to the Barclays Premier League.
Hull manager Phil Brown watched McCormack and Wales midfielder Joe Ledley in Cardiff's 0-0 draw with Celtic on Wednesday.
Cardiff are reluctant to sell and have put a £10million price tag on the pair.
Brown, who is selling defender Sam Ricketts to Bolton, is eager to strengthen his attack.
He is talking to Bobby Zamora of Fulham, although personal terms are not agreed, and has not ruled out a move for free agent Mark Viduka, who is also attracting interest from Portsmouth.
Brown said: 'We have put a contract on the table, a very lucrative contract in terms of what we think of Bobby Zamora. I have not put a timescale on it. A fit Mark Viduka is someone I would be interested in for sure.'