Chelsea midfielder Michael Essien looks set to miss Saturday's clash with Everton after sustaining a hamstring injury against Apoel.
Essien limped off midway through the first half of Tuesday night's 2-2 Champions League draw at Stamford Bridge shortly after firing the Blues' opener.
Carlo Ancelotti revealed Chelsea will assess the extent of the damage on Wednesday but admitted the Ghana midfielder will miss the Premier League showdown with Everton.
"Michael has a problem with his leg. We will look at him over the next few days and check on him tomorrow,'' said Ancelotti. "We hope it's not a big problem. I think he will not be able to play on Saturday.''
Chelsea had already qualified for the knockout stages as Group D winners but Ancelotti was infuriated by a potentially damaging climax to the pool phase.
Apart from Essien's injury, the Italian saw his side peg back Marcin Zewlakow's shock sixth-minute opener only to concede a sloppy late equaliser to Nenad Mirosavljevic, who punished John Mikel Obi's lazy pass.
Essien produced a thunderbolt and Didier Drogba completed a slick team move to haul Chelsea back into contention, but Ancelotti was dismayed by the attitude of his players in the second half.
"This was not a good evening,'' he said. "We did well in the first half after going behind in six minutes. We were playing well and scored two goals. We played with intensity but then lost our concentration. For this I am not happy.
"We have to play for 90 minutes with intensity and concentration. It's a psychological thing. The outcome tonight isn't important but it's important to play our best in every game. This was not how we want it. I spoke with my players about it afterwards.
"The first goal can happen, the second one no. It was the consequence of our soft play. We had the possibility to close the game out but didn't play well.''
Gael Kakuta, the teenager at the centre of Chelsea's suspended transfer embargo, made an impressive full debut and Ancelotti predicted he has a bright future at Stamford Bridge.
The Blues boss added: "Kakuta is the only one who could think. He played well. He showed his talent and made a fantastic pass for the second goal. We have to look at him and stay calm but he will be the future of Chelsea.''
APOEL coach Ivan Jovanovic was left beaming after his Cypriot minnows caused a stir at Stamford Bridge.
"This a very good evening for my team,'' he said. "It's a very important result drawing with one of the top teams in Europe. We knew Chelsea would control the pace of the game. We also knew we had to stay close to them because then we could get something from the game.
"In a game like tonight we knew we wouldn't have many chances and we've been lucky that we were able to score twice in five or six chances.''