Manchester City's Premier League title challenge has been dealt a serious blow with Manuel Pellegrini announcing Sergio Aguero will be out for at least a month.
The Argentina striker has been one of the Abu Dhabi owned club's star performers this season, scoring 12 goals in his last 11 games.
Following their 6-3 mauling of Arsenal on Saturday, City have moved to within three points of the leaders, but news of Aguero's injury will come as a bitter blow to Pellegrini.
The 25-year-old striker had to be taken off during City's 8th home win of the season, with the striker complaining of a problem in his calf.
Speaking on Monday, Pellegrini confirmed that the injury will sideline Aguero until the new year.
"I think he will be at least one month out," the Manchester City manager said. "He has a calf injury. Maybe the doctor can say exactly how many weeks he will be."
News of Aguero's absence comes at an unwanted time for City, who face a crucial encounter with title rivals Liverpool over the busy festive period.
The Argentine also stands to miss league games against Swansea City and high flying Newcastle United, as well as a trip to Blackburn Rovers in the FA Cup third round.
In the former Atletico Madrid striker's absence, Pellegrini is likely to turn to either Edin Dzeko or Stevan Jovetic to fill the void left by City's top scorer.
Jovetic recently returned to action following a calf injury and could be in line to start the team's Capital One Cup quarter-final against Leicester City on Tuesday.
