Fellaini's protracted move to Besiktas has not yet been completed, claims the Sun, and Los Che are ready to pounce on the Belgian.
The 29-year-old is out of contract at the end of the season and will be able to talk with other clubs in January.
Valencia are confident they will be able to lure the midfielder to the Mestalla, with Champions League qualification looking increasingly likely.
Pereira, who is currently on loan with the La Liga club, has expressed a desire to stay at the club on a permanent basis.
He told Super Deporte: "Sure, it's a very good option for me, it would be positive. I'm happy at Valencia."