The 20-year-old spent last season on loan at De Kuip and helped them to second in Eredivisie, their highest league position since the 2000-01 season.
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"Guidetti is getting too much attention," Koeman told De Telegreaaf.
"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."
The former Netherlands international admitted that his team needed a goal scorer after they failed to progress in the Champions League qualifying rounds after being defeated by Dynamo Kiev.
However, Koeman realises that loaning players from other clubs brings pressure and he thinks it’s hard to find a player who can handle that sort of pressure.
"So you must go for a loan from big clubs, where they also pay big salaries," Koeman added.
"If a guy like that comes to Feyenoord, people expect he will score 20 or 30 goals. So a striker must handle that pressure, it's hard to find a guy like that."