Manchester City are still waiting to learn the full extent of defender Matija Nastasic's ankle injury.
There are fears the Serbia centre-back could miss the start of the season after being carried off on a stretcher during the Barclays Asia Trophy clash against Sunderland in Hong Kong at the weekend.
Manager Manuel Pellegrini, speaking at a press conference in Germany, said: "We will have to wait to find out how serious the injury to Nastasic is.
"At this moment, we don't know whether he needs an operation or if there is another solution but I have a lot of players that I can rely on.
"There are enough players who can come in to replace any that are missing."
With Kolo Toure having left City for Liverpool, Nastasic's injury could allow Joleon Lescott the opportunity to reform his successful defensive partnership from the 2012 title-winning season with Vincent Kompany.
Pellegrini said: "The whole squad is here except for Matija.
"I don't know who will play against Milan yet. It's more important we see who is fit and who is ready to play."