The goalkeeper was dropped in favour of Costel Pantilimon at the end of October following a run of high-profile errors, but turned out for England against Germany on Tuesday.
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"I think at this moment that maybe Joe needs a rest but we still have a lot of trust in Joe and he's still a very important player in our squad," Pellegrini told Sky Sports News Arabia.
"I am absolutely sure that this will be an important thing for him to come back to his performances of the last two years."
Pantilimon has started City’s last four games, having previously only featured in a handful of domestic cup ties since joining the club in 2011.
Goal has previously reported that City are monitoring a number of options to challenge Hart in the long-term, with Willy Caballero top of the list and Iker Casillas also in the mix.
In the interim, however, Pellegrini feels it is only fair that Pantilimon is given an opportunity to impress after biding his time on the bench.
"It's very important for me as a manager - you don't have 11 players - you have 22,” he said.
"I analyse what they do every week - I talk with them."