Pantilimon made his Premier League debut in Saturday's 7-0 demolition of Norwich and Pellegrini has confirmed he will continue.
Pellegrini said: "I don't when Joe will come back to the team. It is very important for him to have a rest.
"He has played all the matches for two-and-a-half years.
"We will see in the future what we must do. For today, Pantilimon is playing."
Manchester City Fixtures
Tuesday November 5
19:45 Champions League - Group D
Manchester City v CSKA Moscow
Sunday November 10
14:05 Premier League
Sunderland v Manchester City
Sunday November 24
13:30 Premier League
Manchester City v Tottenham
Wednesday November 27
19:45 Champions League - Group D
Manchester City v Plzen
Sunday December 1
16:10 Premier League
Manchester City v Swansea City
Wednesday December 4
20:00 Premier League
West Brom v Manchester City
Saturday December 7
15:00Premier League
Southampton v Manchester City