Roy Hodgson has confirmed Duff has travelled to London for a medical ahead of his proposed switch from Newcastle to Fulham.
Roy Hodgson: "I think he's been allowed to come down and he's having a medical.
"If all goes well I'm hoping the details will be finalised both on his personal contract and the details between ourselves and Newcastle.
"I'm hoping that will be finalised at the beginning of next week and, all being well, I'll be able to tell you he's a Fulham player next week.
"Until it's completed, it's better to be prudent, but I'm very hopeful we'll have Damien with us."