Hull City have slapped in a club record £12 million bid for Real Madrid striker Alvaro Negredo.
"The greatest virtue in the transfer market is patience," Tigers chairman Paul Duffen told the Hull Daily Mail.
"Alvaro's been on our priority list since May but it's a difficult deal.
"There's no difficulty in terms of the price of the deal, there's no difficulty in terms of the player wanting to come to the Premier League, but it's the complexities of the transaction that make it difficult. It's not about dates or times, it's about getting the right deal for the club."
He added: "Real Madrid historically tend to want a mechanism where they cover themselves and they want to do that again.
"They don't need to lose the connection with Alvaro, they see him as a Galactico going forward.
"It's a complex deal but on the same note, we need to make sure it's the right deal for us as well.
"I have to cover all eventualities and it's those details that mean there's a lot of negotiating, but we're getting closer."