Manchester City midfielder Samir Nasri will be out for eight weeks with a left knee injury, robbing the team of one of their most consistent performers for a crucial period of the season.

Nasri wrote on his Twitter page on Monday that he partially ruptured ligaments in his knee when he was fouled by Newcastle defender Mapou Yanga-Mbiwa in the second half of City's 2-0 win in the Premier League on Sunday. He added that there was also excess swelling on the knee.

"Thank you everyone for your kind words and overwhelming support," Nasri wrote, "i suppose its kind of good news that i will be out around 8 weeks."

Nasri's prognosis allays fears that the France international could miss the World Cup in Brazil.

The City games he is likely to miss include both legs of the last-16 match with Barcelona in the Champions League as well as the League Cup final at Wembley Stadium on March 2, provided that City comes through their semi-final against West Ham. City are ahead 6-0 after the first leg.

The Manchester derby, currently scheduled for March 1, would have to be moved should one or either of the teams reach the League Cup final.

Nasri has been one of City's best players this season, finding his top form under new manager Manuel Pellegrini after struggling at times under previous coach Roberto Mancini last year.