"Benjamin Mendy will be out for 10 to 12 weeks", Guardiola told a news conference ahead of Saturday's visit to West Ham.
Silva, meanwhile, picked up a knock while playing for Portugal during the worldwide break and will be unavailable against West Ham, and possibly Lyon in the Champions League too.
"Everybody wants to play and wants to be part of games", said Guardiola. "The injury is not too big but I don't know if next Tuesday he will be available".
He partnered Manchester City's John Stones in England's 2-1 win over Croatia last Sunday and helped his national side qualify for the UEFA Nations League semi-finals in Portugal next year.
Manchester City striker, Sergio Aguero, has said they are the only team that can stop themselves from winning the Premier League title this season.
"I don't think many teams have managed to win back-to-back".
Manuel Pellegrini insists West Ham will take the game to Manchester City despite the memory of some recent hidings.
"I am a better manager than I was in Germany, and I am a better manager now than I was at FC Barcelona by far, just for the fact of being there", he said at the Peers Annual Lecture at Liverpool University. 'They are very good and they have good players, but it's possible to beat them.
Attentions will now gradually turn towards the forthcoming January transfer window, as Premier League clubs begin considering brining in some potential reinforcements for the midway stage of the season.
"Maybe I will change my mind later but I am fully convinced in my mind here".