The 21-year-old Sweden striker missed the start of the season while recovering from knee surgery.
It followed his battle with a debilitating virus he suffered while on loan at Feyenoord.
Guidetti hasn't played for City's first team since 2010 and Pellegrini revealed his return is 'good news'.
The City boss said: "John starts this week working normally with the whole squad. So that is very good news for him and for the team and we see in the future what will happen with him.
"We must see how he improves every week.
"There is a lot of time with injuries so we will see."
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