The Spain international suffered a thigh injury while away on international duty last week and will not face Stoke City on Saturday.
However, Pellegrini has confirmed that Silva could play a part in the Chilean's first Manchester derby at the Etihad Stadium on September 22.
"We will see about Silva next week," the City boss said.
"We will try for the derby – if he’s 100 per cent he can play in that game."
Silva will miss Saturday's trip to the Britannia Stadium, with Micah Richards (hamstring), Gael Clichy (knock), Martin Demichelis (knee) and captain Vincent Kompany (groin) also ruled out.
Kompany, however, is also likely to return for the clash with David Moyes' side, following the injury he suffered in his City's first game of the season against Newcastle United.
"Vincent Kompany is OK but it’s too much of a risk for him to play this match (Stoke)," he continued.
"(In) two or three more days he will be 100 percent."
City open their UEFA Champions League campaign in midweek against Viktoria Plzen, before facing their local rivals, but Pellegrini is not concerned by the busy schedule.
He added: "It’s a big test for all of the big clubs, all of them are playing the Champions League and Europa League – we have seven games in 21 days.
"It’s the same thing October, November, December - that’s why we have 23, 24 top-class players – we will try to do our best performance in every game we play."
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