The 25-year-old's previous deal with the Blues had been due to expire in 2017.
However, the defender, who scored the only goal of the game in Empoli's 1-0 win over Lazio at the weekend, has now agreed a two-year extension.
Former Italy Under-21 international Tonelli has risen through the ranks at the Stadio Carlo Castellani, having made his debut in 2010.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Napoli | 6 | 4 | 1 | 1 | 11 | 4 | 7 | 13 |
| 2 | Juventus | 6 | 3 | 3 | 0 | 9 | 0 | 9 | 12 |
| 3 | AC Milan | 6 | 3 | 2 | 1 | 14 | 7 | 7 | 11 |
| 4 | Torino | 6 | 3 | 2 | 1 | 10 | 8 | 2 | 11 |
| 5 | Inter Milan | 6 | 3 | 2 | 1 | 13 | 7 | 6 | 11 |
| 6 | Udinese | 6 | 3 | 1 | 2 | 9 | 10 | -1 | 10 |
| 7 | Empoli | 6 | 2 | 4 | 0 | 5 | 2 | 3 | 10 |
| 8 | Lazio | 6 | 3 | 1 | 2 | 12 | 10 | 2 | 10 |
| 9 | Roma | 6 | 2 | 3 | 1 | 7 | 4 | 3 | 9 |
| 10 | Como | 6 | 2 | 2 | 2 | 9 | 11 | -2 | 8 |
| 11 | Atalanta BCAtalanta | 6 | 2 | 1 | 3 | 11 | 12 | -1 | 7 |
| 12 | Bologna | 6 | 1 | 4 | 1 | 7 | 9 | -2 | 7 |
| 13 | Fiorentina | 6 | 1 | 4 | 1 | 7 | 7 | 0 | 7 |
| 14 | Hellas VeronaHellas Verona | 6 | 2 | 0 | 4 | 10 | 11 | -1 | 6 |
| 15 | Lecce | 6 | 1 | 2 | 3 | 3 | 11 | -8 | 5 |
| 16 | CagliariCagliari | 6 | 1 | 2 | 3 | 4 | 10 | -6 | 5 |
| 17 | Genoa | 6 | 1 | 2 | 3 | 4 | 10 | -6 | 5 |
| 18 | Parma | 6 | 1 | 2 | 3 | 10 | 12 | -2 | 5 |
| 19 | VeneziaVenezia | 6 | 1 | 1 | 4 | 4 | 10 | -6 | 4 |
| 20 | Monza | 6 | 0 | 3 | 3 | 4 | 8 | -4 | 3 |
| > Serie A Full Table | |||||||||
