Sky Sports Deutschland’s Florian Plettenberg says that Manchester United have made a first enquiry for Serhou Guirassy.
The prolific striker has a clause that will allow him to leave Stuttgart for under €20m in January.
However, Calciomercato reports than AC Milan have also held positive talks over a deal.
Newcastle United and West Ham United have also been linked.
Stuttgart want to strike a deal which will see the 27-year-old remain at the club until the end of the season.