The 18-year-old centre-back, who signed his first professional contract in March, has attracted strong interest from Serie A since earning his first call-up to Italy's senior squad in June, with several Italian clubs said to be tracking the 1.94m defender.
Reggiani, who plays predominantly with his right foot, would reportedly be open to a return to his home country given the opportunity.
A sale is not being ruled out at Borussia Dortmund, largely because of the sheer weight of competition Reggiani faces in central defence. Nico Schlotterbeck, 26, Waldemar Anton, 30, Ramy Bensebaini, 31, and Emre Can, 32, are all established options, while summer arrival Joane Gadou, 19, and 20-year-old Filippo Mane add further depth to a crowded department alongside Reggiani himself.
According to Bild, Dortmund's priority among the younger options is Gadou, who is regarded as a bigger long-term project than Reggiani. Should an attractive offer arrive for the Italian this summer, the report suggests the club would "at least have to think it over" rather than dismiss it outright, leaving his immediate future at Signal Iduna Park genuinely in the balance despite the progress he showed last season.
Reggiani's rise last season was rapid by any standard. Having arrived at Dortmund's academy as a largely unheralded prospect, he forced his way into Kovac's plans during a run of squad rotation and injuries, impressing enough with his composure on the ball and reading of the game to retain his place in several Bundesliga fixtures as well as a Champions League appearance.
That form was rewarded not only with his first professional contract but with a maiden call-up to Italy's senior squad, a remarkable achievement for a player who had barely established himself at club level twelve months earlier.
With so many senior centre-backs already on the books and further competition emerging from within the academy, Dortmund's willingness to at least entertain offers reflects the practical reality of a position where opportunities for Reggiani may remain limited even after his breakthrough campaign.