Hayles, 32, scored 57 goals in 143 starts for the London club, and has been told that he can leave Craven Cottage now that his contract has expired.
He said: "I've spoken to Leeds but it's early stages. They are a massive club that should be in the Premiership and I'd have no qualms about moving there.
"But I'm going to take my time. I've had a few offers and I'm looking forward to a new challenge."