Hart, previously City's established number one, was dropped from the team in October after making a string of high-profile errors, which included mistakes in the 3-1 home loss to Bayern at the Etihad Stadium earlier that month.
If he faces the German side again on Tuesday, it will be only his second appearance in the Blues' last 10 games.
It has been a worrying time for the England international this season, building up to next summer's World Cup.
And Pellegrini has no doubt about the potential significance of the contest at the Allianz Arena for Hart.
Manuel Pellegrini: "For him it is a very important game.
"I am not thinking about the past, just thinking about the future. I trust in him."
"I don't think this press conference is for talking about Joe Hart.
"I have said in other weeks what I think about him and his performances. Today is not the day to analyse this."