The Spain international was substituted midway through the second half of City’s 5-2 Champions League win against CSKA Moscow at the Etihad Stadium on Tuesday and Pellegrini has now revealed the extent of the problem.
“He has a problem with his calf. I don’t know exactly how many weeks it will be but maybe three or four,” said the Chilean, who was speaking ahead of his side’s Premier League trip to Sunderland this weekend.
City captain Vincent Kompany also remains on the sidelines with a thigh injury but Pellegrini is hopeful he will be fit for the first game after the upcoming international break, against Tottenham Hotspur on November 24.
The Belgian defender has missed City’s last six games since suffering the injury in the home victory over Everton on October 5.