The veteran goalkeeper will see his current deal at Craven Cottage expire at the end of the season.
Fulham boss Martin Jol has expressed a desire to retain the 40-year-old's services, but has also conceded that he is in the market for a new shot-stopper.
That search may be intensified when the transfer window re-opens, with Schwarzer admitting that he is facing up to an uncertain future.
After starring in a 1-1 draw with Aston Villa on Saturday, the Australia international said: "Who knows? We'll have to wait and see.
"I have a contract until the end of the season, but I want to carry on playing without a doubt.
"I definitely want to play until the next World Cup with Australia.
"I'm no closer to signing a new deal and there aren't any talks at the moment, either.
"I'm just trying to do the best I can and we'll see what happens at the end of the season."