Italian club Sassuolo value the Ghana international at around €15 million (£13.73m), according to Tuttomercatoweb.com.
Duncan has been on the books of Sassuolo since 2015 when he joined from Italian rivals Sampdoria.
The 24-year-old actually started his professional club football career at Italian giants Inter, but the midfielder failed to make an impact at the Nerazzurri.
The Ghana international started 14 Serie A games for Sassuolo last season, scoring one goal and providing one assist in the process, according to WhoScored.
Duncan is a hard-working midfielder who is still quite young and could develop into a very good player in the coming years.
However, Inter are Duncan’s former club, and the midfielder could feel that he has unfinished business at the Nerazzurri.