The Serie A club confirmed the switch on Twitter, revealing that the 29-year-old has successfully passed a medical.
Valdifiori will link up with his former manager Maurizio Sarri at Napoli, with the Italian unveiled as Rafael Benitez's successor last week.
The midfielder is a full Italy international, having earned his first cap in the 1-1 draw against England in March.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Napoli | 7 | 5 | 1 | 1 | 14 | 5 | 9 | 16 |
| 2 | Inter Milan | 7 | 4 | 2 | 1 | 16 | 9 | 7 | 14 |
| 3 | Udinese | 7 | 4 | 1 | 2 | 10 | 10 | 0 | 13 |
| 4 | Juventus | 7 | 3 | 4 | 0 | 10 | 1 | 9 | 13 |
| 5 | Lazio | 7 | 4 | 1 | 2 | 14 | 11 | 3 | 13 |
| 6 | AC Milan | 7 | 3 | 2 | 2 | 15 | 9 | 6 | 11 |
| 7 | Torino | 7 | 3 | 2 | 2 | 12 | 11 | 1 | 11 |
| 8 | Atalanta BCAtalanta | 7 | 3 | 1 | 3 | 16 | 13 | 3 | 10 |
| 9 | Empoli | 7 | 2 | 4 | 1 | 6 | 4 | 2 | 10 |
| 10 | Fiorentina | 7 | 2 | 4 | 1 | 9 | 8 | 1 | 10 |
| 11 | Roma | 7 | 2 | 4 | 1 | 8 | 5 | 3 | 10 |
| 12 | Hellas VeronaHellas Verona | 7 | 3 | 0 | 4 | 12 | 12 | 0 | 9 |
| 13 | Bologna | 7 | 1 | 5 | 1 | 7 | 9 | -2 | 8 |
| 14 | Como | 7 | 2 | 2 | 3 | 10 | 14 | -4 | 8 |
| 15 | CagliariCagliari | 7 | 1 | 3 | 3 | 5 | 11 | -6 | 6 |
| 16 | Parma | 7 | 1 | 3 | 3 | 10 | 12 | -2 | 6 |
| 17 | Lecce | 7 | 1 | 2 | 4 | 3 | 12 | -9 | 5 |
| 18 | Genoa | 7 | 1 | 2 | 4 | 5 | 15 | -10 | 5 |
| 19 | Monza | 7 | 0 | 4 | 3 | 5 | 9 | -4 | 4 |
| 20 | VeneziaVenezia | 7 | 1 | 1 | 5 | 5 | 12 | -7 | 4 |
| > Serie A Full Table | |||||||||
