Raheem Sterling is expected to be out for six to eight weeks with the groin injury he suffered during Sunday’s Manchester derby.
The winger was forced off midway through the first half of City’s 1-0 defeat to United at the Etihad Stadium.
Speaking after the game, City boss Manuel Pellegrini suggested the £49million summer signing would be out of action for around a month.
But scans are understood to have shown the injury is more serious than first thought and Sterling is now facing up to two months on the sidelines.
The 21-year-old is now set to sit out nearly all if not the whole of the rest of City’s Premier League campaign, which has eight more fixtures and ends with a trip to Swansea on May 15.
The Champions League final is not until May 28, so if City – who take on Paris St Germain in the last eight – make that, he should be back available by then.
England will also be monitoring the situation closely as their preparations for Euro 2016 continue.
There is better news for City and England, however, with regards to Joe Hart.
The goalkeeper picked up a calf injury against United but is expected to return within the next fortnight.