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 | |
| C | Inter Milan | 36 | 29 | 5 | 2 | 86 | 19 | 67 | 92 |
| 2 | AC Milan | 36 | 22 | 8 | 6 | 72 | 43 | 29 | 74 |
| 3 | Bologna | 36 | 18 | 13 | 5 | 51 | 27 | 24 | 67 |
| 4 | Juventus | 35 | 18 | 12 | 5 | 48 | 27 | 21 | 66 |
| 5 | Atalanta BCAtalanta | 34 | 18 | 6 | 10 | 63 | 38 | 25 | 60 |
| 6 | Roma | 35 | 17 | 9 | 9 | 62 | 42 | 20 | 60 |
| 7 | Lazio | 35 | 17 | 5 | 13 | 45 | 37 | 8 | 56 |
| 8 | Napoli | 36 | 13 | 12 | 11 | 53 | 46 | 7 | 51 |
| 9 | Fiorentina | 34 | 14 | 8 | 12 | 51 | 39 | 12 | 50 |
| 10 | Torino | 35 | 11 | 14 | 10 | 31 | 31 | 0 | 47 |
| 11 | Monza | 35 | 11 | 12 | 12 | 38 | 46 | -8 | 45 |
| 12 | Genoa | 35 | 10 | 13 | 12 | 41 | 43 | -2 | 43 |
| 13 | Lecce | 35 | 8 | 13 | 14 | 32 | 50 | -18 | 37 |
| 14 | Hellas VeronaHellas Verona | 35 | 8 | 10 | 17 | 33 | 46 | -13 | 34 |
| 15 | CagliariCagliari | 36 | 7 | 12 | 17 | 38 | 65 | -27 | 33 |
| 16 | Empoli | 35 | 8 | 8 | 19 | 26 | 50 | -24 | 32 |
| 17 | FrosinoneFrosinone | 36 | 7 | 11 | 18 | 43 | 68 | -25 | 32 |
| 18 | Udinese | 35 | 4 | 18 | 13 | 33 | 52 | -19 | 30 |
| 19 | SassuoloSassuolo | 35 | 7 | 8 | 20 | 41 | 70 | -29 | 29 |
| R | Salernitana | 35 | 2 | 9 | 24 | 27 | 75 | -48 | 15 |
| > Serie A Full Table | |||||||||
