A scrum of teams have been linked to Sas, who enhanced his reputation with a fine showing in the World Cup finals in June.
Inter are the latest team to express interest, with Sierra Leone ace Kallon reportedly being offered as bait for the forward.
Kallon would seem to be an attractive proposition, but Gala do not want to sell one of their prized assets as part of the deal.
A Gala board member said: "We know that there are offers from all over Europe for Hasan, but we have an agreement for one year. We will discuss again with Hasan at end of the season.
"Terim wants to see Mohammed Kallon at Galatasaray. But we need Hasan too."
Sas seems content in Istanbul for a further season, saying: "I'm happy at Galatasaray. I will stay here for one more year."
