The forward has fallen down the pecking order at the Spanish club and he has been linked with a move away in January.
Everton are particularly keen on the France international as they continue their hunt for a new striker.
Originally it was thought Gameiro would jump at a move to Goodison Park, but now the 30-year-old has revealed he may stay at Atletico and fight for his future.
"I am at a great club with lots of competition for places," Gameiro told Diario AS.
"Everybody has to compete to earn a starting place at the club and I am not worried about that at this moment, I am not afraid.