Kostic has spent 2 seasons at Eintracht Frankfurt, playing 66 games and scoring 16 goals.
The Serbian midfielder knows the German league perfectly since he has also had spells at Hamburg and Stuttgart.
But Kostic could wave goodbye to the Bundesliga to play in Serie A for the first time, as clubs such as Inter Milan and AC Milan are interested in signing him.
That is what 'Calcio Mercato' say, who speak of a standoff that will take place between both clubs in the January window, a fight that will take place in June 2020 if neither of the clubs manage to convince Eintracht Frankfurt.