Manchester City striker Sergio Aguero will be out for at least a month after suffering a calf injury.
The in-form Argentinian suffered the problem early in the second half of Saturday's impressive 6-3 defeat of Arsenal at the Etihad Stadium.
Among the games the 25-year-old is set to miss is the home clash with Liverpool on Boxing Day.
City boss Manuel 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 in all competitions, 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."
Aguero took to his Twitter account to keep City fans updated on developments.
He tweeted: "It's confirmed - my calf injury will leave me out for at least a month. The good news is recovery work starts today!
"We started with therapeutic massages on the area and some bike work. I'll keep you posted. Thanks for the support!"