Leighton Baines has been ruled out for up to six weeks after a scan revealed a tear on his hamstring.
Defender Baines is likely to be out until January
Everton initially hoped the full-back, who has just turned 23, would be out for only two weeks after he pulled up sharply during the 3-0 win over Fulham.
But manager David Moyes told the Everton website: "It looks like Leighton is going to be out for between four to six weeks.
"It's a blow because he has done so well for us."
Everton were eager for the former Wigan defender to return for the hectic festive programme.
They had planned to give him intensive treatment to try to get him back for the Christmas fixtures.