(CNN) -- Manchester City striker Mario Balotelli is to undergo a knee operation which will rule him out of action for up to six weeks.
The Italian international joined City from Inter Milan just before the transfer window closed in August, but has been struggling with the injury that City hoped would not require surgery.
The 20-year-old has now returned to Milan after City confirmed the injury to his lateral meniscus on their official website.
"Balotelli's injury is to the lateral meniscus, one of the two most crucial structures in the knee, and medical wisdom is to try and encourage the problem to heal without recourse to an operation.
"It was hoped that the symptoms would settle down but once Balotelli began to step up his recovery program this week, it became clear that action would need to be taken."
Balotelli is expected to miss the Premier League match against Chelsea and the Europea League tie with Juventus.
However, City are hopeful he will return for the visit of potential title rivals Arsenal on October 24.