City spent £32million to bring the France international to the Etihad Stadium over the summer, making him the most expensive defender in the club’s history.
Having invested so heavily in the 23-year-old, it was expected that he would be thrown straight into Premier League action.
Mangala was, however, given an extended rest following his World Cup exploits and is still waiting on his City bow.
He will be in contention for a meeting with Arsenal after the international break, but he faces a tough task to break up a productive partnership between Vincent Kompany and Martin Demichelis.
Pellegrini said on his options at centre-half: “He (Mangala) can bring a lot. He is a very strong defender, who is very fast.
“He is only 23 so he can still improve a lot, which is what we were looking for.
“We are helping him to settle here in Manchester and after the international break he will be able to play.
“We need the three of them.
“Like I have said about the strikers, it’s the same with the defenders.
“We have so many games to play. At the moment Demichelis and Kompany are playing well but that doesn’t mean that Mangala can’t play as well.
“He will have his time to play, and then it will depend on his performances for the team.”