The Iran international has helped his country to book a place at Brazil 2014, and he is determined to be in their 23-man squad.
He must, however, be playing at club level if he is to be considered.
Just three starts this season, coming off the back of an ankle problem at the end of the last campaign, have left the 27-year-old sweating on his place on the plane.
He said in the Daily Mirror: "It's a big year for me. It's a dream to play in the World Cup and I have the chance to do that next summer, so it's very important that I'm playing.
"The manager tells us every time that we have to be playing for our clubs because you need games to be sharp heading into the tournament.
"If you're not playing you're scared about your World Cup chances, so hopefully I'm fit and ready."
Dejagah has offered no indication that he is looking for a route out of Craven Cottage, with starts made in Fulham's last two outings against Manchester United and Liverpool.
He added: "I was out for a long time and I'm pleased to be back.
"I feel good, but I know I have to work hard because we've got some good new players.
"I believe in myself so I want to show the coach I deserve to play.
"We have a lot of players on the wing, but it's good for me, because it brings out the best in everyone."