The 22-year-old £10.4million signing from Hamburg was due to make a late return for pre-season training anyway after starring in Germany's run to the World Cup semi-finals.
But he aggravated a knee injury in a bizarre collision with an in-flight meals trolley last month, condemning him to a further period of rehabilitation.
Only last week was Boateng able to join the City squad in training and he was far from fully fit on Saturday, meaning Mancini preferred to use him off the bench.
However, with Juventus due in Manchester later this week and then Newcastle on Sunday, the Blues boss is deciding what route to take next.
"Maybe Boateng will get a start," said Mancini. "He needs to take things very softly because I don't think he is quite ready yet.
"He needs to work and train."