According to a report in Calciomercato, the Serbian international's future at the Bundesliga side has been put in jeopardy after two impressive seasons at the Westfalenstadion.
United have been continually linked with a move for a defender this summer with Nemanja Vidic refusing to commit his future to the Red Devils, and it's believed that Sir Alex Ferguson has identified Subotic as the perfect replacement for his compatriot.
However, they will reportedly have to fend off interest from Arsenal for the centre-back, who is valued at £25 million by his German employers.
Subotic, who represented the United States at youth level, joined Borussia for a reported fee of €4m (£3.3m).
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