Manchester City face an anxious wait to see if John Stones will be fit to face Liverpool later this month. The England defender, who has only made six appearances in an injury-hit season, came off at half-time in Tuesday’s win over Young Boys of Bern and manager Pep Guardiola has ruled him out of Sunday’s trip to Chelsea. Guardiola said Stones’ muscular problem is not as serious as he initially feared but is unsure when the 29-year-old will be fit again and he has a race against time to be available for the clash with Liverpool on 25 November. The City manager explained: “He’s not ready for tomorrow [game against Chelsea on Sunday] and we will see when we come back from the international break. I don’t know. “The doctor said to me it’s not as bad [as feared] but I still don’t know. I want to create tempo. When he’s going to be fit again, he’s going to come back.” Stones was reinvented last season to operate partly as a midfielder in addition to his duties at the back and Guardiola believes summer signing Josko Gvardiol is not yet ready to take up a similar role, coming forward in possession. “Still he didn’t prove it in training sessions and drills that we do to see how you move in more central positions,” he said. “Still I didn’t see it. Maybe in future, because he is still young and at the beginning we didn’t expect John could do that but he can do that because he has been here eight years.” Rico Lewis is able to play both as a full-back and in midfield and Guardiola believes that, were he bigger, the teenager would be one of the outstanding footballers in the division. He added: “If he was a little bit taller, we would consider him one of the best players in the Premier League. He is so small but he is an exceptional player.” Kevin de Bruyne, who has been out since August and has undergone an operation on his injured hamstring, has had a further scan this week. The Belgian is expected to be out for the rest of the calendar year but Guardiola has not put a timeframe on his comeback. He added: “I spoke with him two days ago and he said he feels really good but it’s not necessary to take bad decisions or wrong decisions in coming back early and getting injured again. Kevin was a tough injury, a surgery.” Read More Jeremy Doku’s brilliance shows Man City’s edge and Chelsea’s key problem Rumours: Man United could sell duo in January and Newcastle target midfield pair How can Man United qualify in Champions League?