The 24-year-old, who has scored two Premier League goals in three games this season, has reportedly attracted interest from a host of European clubs.
"I begin now to my fifth season at Everton. This will be one of my last. I've seen everything. In January or at the end of the season I would look for another club or league," he told Het Nieuwsblad.
The Belgian recently signed a new five-year contract at Goodison Park.