The highly-rated Sweden striker joined City as a 16-year-old from IF Brommapojkarna 2008 but has made just one first-team appearance for the Premier League club.
It is unclear whether new City boss Manuel Pellegrini sees a future for Guidetti at the Etihad Stadium, though he is currently part of the first-team squad for their pre-season tour of South Africa.
The 21-year-old, who has also been linked with a move to Sunderland, has been sent out on three separate loan spells, including a season-long loan to Feyenoord in 2011/12.
He scored 20 goals in 23 appearances for the Eredivisie outfit to become an instant crowd favourite at De Kuip.
Van Geel says the club would welcome him back with open arms should he be made available, though he stressed no deal was imminent.
"Guidetti is in our hearts and the door is always open for him," he told the AD newspaper.
"If a godsend occurs, we would naturally increase our squad with him.
"But I would like to say clearly that no concrete efforts have been made to get him."