The DR Congo international was forced off during Sunday's draw with Manchester United, and now faces an extended spell on the sidelines
Everton have confirmed that winger Yannick Bolasie will require surgery on what they describe as a "serious" injury to his knee.
The 27-year-old was substituted in the 68th minute of Sunday's 1-1 Premier League draw with Manchester United and was sent for scans on the problem.
The club have since announced that Bolasie has sustained cruciate ligament damage and will be operated on this week.
"Yannick Bolasie will undergo surgery after sustaining a serious knee ligament injury against Manchester United on Sunday," an Everton statement said.