Bolasie, 27, injured his right knee during the Toffees' 1-1 draw with Manchester United on 4 December.

Manager Koeman said on Wednesday: "It will be around 11-12 months before he is back. That is a big disappointment but he will come back."

Bolasie is due to have a second operation - on his anterior cruciate ligament - in the coming weeks.

The DR Congo international signed for Everton from Crystal Palace in a £25m deal in August, and had played in every league game this campaign up until his injury.

Manchester United's Memphis Depay could be brought in to fill the position in attacking midfield, with Koeman having this season expressed his desire to sign his fellow Dutchman.