The Sweden international proved a hit at De Kuip during a loan spell last season, scoring 20 goals in 23 appearances as Feyenoord finished as runners-up to Ajax.
The 20-year-old's Dutch campaign was curtailed when he picked up a serious virus that caused him to lose all feeling in his right leg and sparked fears for his career.
Guidetti is now on the road to recovery but remains short of match fitness.
His agent has talked up the prospect of him leaving the Etihad Stadium on another loan deal this season, claiming as many as 15 clubs are interested in his services.
Koeman, however, insists Feyenoord are not among them.
"Guidetti is getting too much attention," Koeman told De Telegraaf.
"He's physically not okay and I'm not sure what his situation will be.
"Fans can shout his name from the stands, but it's not realistic.
"With all respect for John, we don't think about him. We're looking for other strikers."