The 31-year-old has been without a club since leaving Siena earlier this year.
He joins an Orient side currently 20th in the League One table, having reached the play-off final last season.
Plasmati, who is 6ft 6ins tall, has also previously played for Catania in Serie A.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Atalanta BCAtalanta | 15 | 11 | 1 | 3 | 38 | 17 | 21 | 34 |
| 2 | Napoli | 15 | 10 | 2 | 3 | 21 | 10 | 11 | 32 |
| 3 | Inter Milan | 14 | 9 | 4 | 1 | 34 | 15 | 19 | 31 |
| 4 | Fiorentina | 14 | 9 | 4 | 1 | 28 | 10 | 18 | 31 |
| 5 | Lazio | 15 | 10 | 1 | 4 | 30 | 17 | 13 | 31 |
| 6 | Juventus | 15 | 6 | 9 | 0 | 24 | 10 | 14 | 27 |
| 7 | AC Milan | 14 | 6 | 4 | 4 | 24 | 16 | 8 | 22 |
| 8 | Bologna | 14 | 5 | 7 | 2 | 20 | 18 | 2 | 22 |
| 9 | Udinese | 15 | 6 | 2 | 7 | 18 | 22 | -4 | 20 |
| 10 | Empoli | 15 | 4 | 7 | 4 | 14 | 15 | -1 | 19 |
| 11 | Roma | 15 | 4 | 4 | 7 | 18 | 21 | -3 | 16 |
| 12 | Torino | 15 | 4 | 4 | 7 | 16 | 20 | -4 | 16 |
| 13 | Parma | 15 | 3 | 6 | 6 | 21 | 25 | -4 | 15 |
| 14 | Genoa | 15 | 3 | 6 | 6 | 13 | 24 | -11 | 15 |
| 15 | CagliariCagliari | 15 | 3 | 5 | 7 | 15 | 25 | -10 | 14 |
| 16 | Lecce | 15 | 3 | 4 | 8 | 8 | 26 | -18 | 13 |
| 17 | Como | 15 | 2 | 6 | 7 | 16 | 28 | -12 | 12 |
| 18 | Hellas VeronaHellas Verona | 15 | 4 | 0 | 11 | 18 | 37 | -19 | 12 |
| 19 | Monza | 15 | 1 | 7 | 7 | 13 | 19 | -6 | 10 |
| 20 | VeneziaVenezia | 15 | 2 | 3 | 10 | 13 | 27 | -14 | 9 |
| > Serie A Full Table | |||||||||
