Aston Villa defender Martin Laursen will be out for up to three months after a scan confirmed he has suffered medial ligament damage to his knee.
Laursen (right) moved to Villa Park from AC Milan for £3m
The Dane sustained the injury during the 4-0 Carling Cup defeat at Chelsea and left Stamford Bridge on crutches.
"It is not looking so good for him," said manager Martin O'Neill. "He is going to be out for quite some time."
The 29-year-old joined Villa from AC Milan in 2004 but knee problems have restricted him to a handful of games.
And O'Neill added: "The only consolation is it's the other knee and not the one where he has
experienced his other problems.
"But you have to feel great sympathy for him because he has worked so hard to get back to fitness.
"The way he has improved from the way he was during pre-season has been terrific and he did well when he came into the team against the likes of West Ham, Watford and Blackburn."
Laursen picked up his injury in a collision with Didier Drogba.
Midfielder Gareth Barry suffered severe bruising to his back in the match at Chelsea and is unlikely to play against Everton.