The 21-year-old midfielder, who spent the second half of last season on loan with the Toffees, is wanted back at Goodison Park.
David Moyes has alluded to an interest in re-signing the Portugal Under-21 international, but will find Benfica in stubborn mood.
The Lisbon club's president Luis Filipe De Vieira is determined to hang on to the youngster and says there have been no offers for Fernandes.
"We have not received any official offers for our player," Vieira told A Bola.
"If any offer arrives, our answer will be negative.
"Manuel is playing to a good level and he is needed for our project this season.
"No doubts exist about this question. The kid will not leave the club."