MANCHESTER: Manchester City captain Vincent Kompany is likely to be sidelined for about a month after suffering a recurrence of a calf problem on Tuesday as his side qualified for the Champions League quarter-finals. Kompany was forced off in the fifth minute but City went on to reach the last eight of the competition for the first time after drawing 0-0 at home to Dynamo Kiev to advance 3-1 on aggregate. 'Vincent again has a muscle injury in his calf,' manager Manuel Pellegrini told reporters. 'We'll know tomorrow, or maybe the day after tomorrow, how bad it is but always a muscle injury is a minimum of one month out.' Belgium central defender Kompany, who only returned from a calf problem in February having been out since December, will have to miss Sunday's home Premier League derby with neighbours Manchester United. 'This is difficult for him because he came back very well and played six games in a row,' added Pellegrini. City kept it tight on Tuesday night, refusing to gamble with their healthy 3-1 first-leg victory. 'We didn't take any risks,' said Pellegrini. 'For our team it was important to keep the ball and not allow them to create chances. 'They knew before the game they had to score three goals and that's not easy. We didn't have too many chances because we didn't force the game. 'We normally are a team that always scores. We've received a lot of criticism that we never keep clean sheets but we've kept a clean sheet for the last three games,' said Pellegrini.