Donati, who has also been linked with AC Milan, has revealed he is prepared to take a pay cut in order to return to Italy.
“I am very devoted to Atalanta,” Donati told Italian radio.
“I only know that in Bergamo someone really appreciates me and, if they would like me, I’d be ready to talk. For sure, Celtic won’t stand on my departure.
“I am getting on well in Scotland, but they know Italy is my home and I know one day I’ll be back in Bergamo.
“It could be in the summer or it could be in two years. Atalanta are performing well in the championship. They’ve got very good skilled midfielders. My possible deal would mean a further option for them.
“I’d be available to deal with any of Atalanta’s requirements – it’s the club that made me a player.
“Maybe not a 50 per cent cut of my salary, but if we should come to discuss things seriously there wouldn’t be any problem.”