Yannick Bolasie could be out for as long as a year, according to his Everton manager Ronald Koeman.
The £28m summer signing had knee surgery last month after damaging a cruciate ligament and a meniscus during Everton's 1-1 draw with Manchester United at the start of December.
A second operation is pending, and Koeman admitted shortly after the injury occurred that Bolasie would be missing "for a long time".
And speaking at the club's Annual General Meeting on Wednesday Koeman put a timescale on the winger's absence.
He said: "It is a long-term injury - 10, 11, 12 months. He will come back, he has a strong mentality."
Everton have already lined up cover in the shape of Charlton teenager Ademola Lookman, who is expected to complete a £10m move to Goodison Park in the next 24 hours.