Crystal Palace captain Scott Dann will be out for at least "a few weeks" after suffering a knee ligament injury in Saturday's 2-1 victory at Chelsea.
Dann came on as a half-time substitute at Stamford Bridge following an injury to fellow centre-back James Tomkins.
But the 30-year-old had to be withdrawn 15 minutes later after twisting his knee while blocking a Diego Costa shot.
Palace boss Sam Allardyce said the injury was "more serious than we first thought".
"He'll be in a brace for two or three weeks and then we'll go from there," he added.