Fulham boss Martin Jol admits they're ready to discuss new terms with a raft of senior players.
Talks with a number of those are already underway, and Jol hopes they will join Duff in committing their futures to Craven Cottage.
He said: "There's a lot of players finishing their contracts [at the end of the season] and we are talking to most of them.
"We will have a few more in the next couple of weeks.
"There's a couple with clauses if they play more than 25 matches will get an automatic extension."