The 30-year-old has rejected a new contract offer from the Cottagers.
Johnson is keen on a deal that would keep him at Fulham until the summer of 2014, while the club have only offered the striker a deal which runs until 2013.
Johnson told the Sunday Mirror: “They have made me an offer to stay and I don’t feel it’s appropriate to go into the details of that offer.
“But I have to take into account many things before I can commit my future to the club and I feel the contract should reflect my worth.
“It will be the last big contract of my career and primarily I have to do what is right by my family. And if the contract doesn’t reflect that then I will weigh up my options.
“I have faced adversity in my career but I would like to think the Fulham supporters have always appreciated that I have given my best when I played.”
