The Brazil international was one of few players to impress in a dismal 2012-13 campaign that saw the club relegated, but an expected summer move away from Loftus Road never materialized and the 34-year-old has since fallen behind Robert Green in the pecking order.
With just one appearance for Harry Redknapp's side this season, the former Inter shot-stopper is likely to leave as he eyes more game time ahead of the World Cup - and Fernandes is anticipating a January exit.
When asked if Cesar is likely to leave Loftus Road this month, Fernandes told Sky Sports News: "I think so. It's a waste for someone with such immense talent not playing and I think he is one of the best goalkeepers in the world, so I'm sure someone will pick him up and let's see how that goes.
"We've gone with Rob [Green] because at the beginning of the season we thought Julio wouldn't be there. Rob has come in and done a fantastic job and I think he could be pushing for an England place - he's played really well. Just look at the last game [a 2-1 home victory over Huddersfield Town on Saturday]. He kept us in the game until we came back and won. He's been superb."
QPR boss Redknapp had previously said he would not stand in the way of Cesar should he seek a move away, and would even let the Brazilian leave for free.