Fiorentina's starting lineup will include Terracciano, Venuti, Milenkovic, Pezzella, Caceres, Biragi, Pulgar, Castrovilli, Bonaventura, Ribery, Vlahovic.
After 36 rounds of Serie A, Fiorentina scored 39 points and took 13th place.
Napoli is in fourth position with 73 points.
The Fiorentina - Napoli match will take place on 16 May.
The meeting will take place at the Artemio Franchi stadium in Florence.
The game starts at 13:30 Moscow time.