Manchester City striker Sergio Aguero could be out for at least a month, according to manager Manuel Pellegrini.
The in-form Argentinian suffered a calf injury early in the second half of Saturday's impressive 6-3 defeat of Arsenal at the Etihad Stadium.
City are not yet sure how long the 25-year-old could be out but among the games he is set to miss is the home clash with Liverpool on St Stephen's Day.
Pellegrini, asked at a press conference if Aguero might miss the Christmas programme, said: "I think he will be, at least, one month out.
"He has a calf injury. Maybe the doctor can say exactly how many weeks he will be."
Aguero has been in outstanding form this season, scoring 19 goals, 18 of which have come in his last 16 appearances.
His partnership with new signing Alvaro Negredo has also been prolific, with the Spaniard contributing 13 goals to the City cause.
He is certain to be missed in his absence although, on the positive side, £22million summer signing Stevan Jovetic is now in contention after an injury-hit start to his City career.
The Montenegro international, most recently sidelined by a calf injury, has managed just five appearances since his arrival.
In defence Micah Richards and Matija Nastasic are still unavailable.
Pellegrini, speaking ahead of the midweek Capital One Cup quarter-final at Leicester, said: "The players that are injured are Micah Richards, he continues to be injured, and Nastasic also and Aguero.
"All the other players are available. We will see which 18 players we pick. Jovetic is okay."