In as much as Kevin de Bruyne is one of the best player on Manchester City but I don't think he will play this match even if he is free from the injury this week, because whenever a player has that kind of injury and stay that long without training he would find it difficult to perform if being put in the field so Kelvin de Bruyne will not start immediately after recovery because he will need to undergo a series of fitness test and training to actually know if he can perform when he resumes training.
So perhaps even if Kelvin de Bruyne were to play there upcoming match I don't think he will be a much threat to other team because he will not be able to play the way he normally do.
De Bruyne will not return to the game until January - February, so it is pointless to discuss his possible appearance in the match with Liverpool. City are playing well without De Bruyne, Guardiola never built the team’s game on one player and although Kevin has become a very important player in Guardiola’s scheme, now City are coping quite well without him.
Liverpool are not playing their best away, they have won only one of their last five games against Bournemouth, they have drawn two and lost two, while City look great at home and rarely drop points.
Indeed, they still show something good even without KDB but they will be better in the game if KDB is in it. I don't know for sure whether he will be able to play or not in this big match, because I also see the same thing, even though a player is said to have recovered from his injury, but they also still have to do several stages to really be able to play. It will be very risky if they force him to play when he is not really ready, instead of being able to help it will risk him getting the next injury.