The Ghanaian has been revealed as the primary midfield target for Fiorentina gaffer Giuseppe Iachini.
Giuseppe Iachini has been impressed by the performances of the midfielder and sees him to possess a perfect blend of tactical sense and strength.
Sassuolo have placed an 18 million euro price tag on him but will be willing to let him go for a player plus cash deal. Fiorentina are willing to part ways with 20 year old winger Riccardo Sottil, who has failed to impress since the start of the season.
Sottil has played 15 matches in all competitions and has been directly involved in one goal (1 goal, 0 assists).
Duncan however has been a regular fixture for the Serie A side with 19 appearances in all competitions. He has scored once and assisted a further five.