Hart pulled off several impressive saves in England's 1-0 defeat against Germany despite being dropped for City's last four games.
However, Pellegrini believes Hart's time out of the first team will do him good.
"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 News Arabia.
"It's very important for me as a manager - you don't have 11 players - you have 22.
"I analyse what they do every week - I talk with them.
"I am absolutely convinced he will come back to his performances of the last two years."