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 | 17 | 13 | 1 | 3 | 42 | 19 | 23 | 40 |
| 2 | Napoli | 17 | 12 | 2 | 3 | 26 | 12 | 14 | 38 |
| 3 | Inter Milan | 15 | 10 | 4 | 1 | 40 | 15 | 25 | 34 |
| 4 | Lazio | 17 | 11 | 1 | 5 | 32 | 24 | 8 | 34 |
| 5 | Fiorentina | 15 | 9 | 4 | 2 | 28 | 11 | 17 | 31 |
| 6 | Juventus | 17 | 7 | 10 | 0 | 28 | 13 | 15 | 31 |
| 7 | Bologna | 16 | 7 | 7 | 2 | 23 | 18 | 5 | 28 |
| 8 | AC Milan | 16 | 7 | 5 | 4 | 25 | 16 | 9 | 26 |
| 9 | Udinese | 16 | 6 | 2 | 8 | 19 | 25 | -6 | 20 |
| 10 | Roma | 17 | 5 | 4 | 8 | 23 | 23 | 0 | 19 |
| 11 | Empoli | 17 | 4 | 7 | 6 | 16 | 19 | -3 | 19 |
| 12 | Torino | 17 | 5 | 4 | 8 | 17 | 22 | -5 | 19 |
| 13 | Genoa | 17 | 3 | 7 | 7 | 14 | 26 | -12 | 16 |
| 14 | Lecce | 17 | 4 | 4 | 9 | 11 | 29 | -18 | 16 |
| 15 | Parma | 17 | 3 | 6 | 8 | 23 | 33 | -10 | 15 |
| 16 | Como | 16 | 3 | 6 | 7 | 18 | 28 | -10 | 15 |
| 17 | Hellas VeronaHellas Verona | 17 | 5 | 0 | 12 | 21 | 40 | -19 | 15 |
| 18 | CagliariCagliari | 17 | 3 | 5 | 9 | 16 | 28 | -12 | 14 |
| 19 | VeneziaVenezia | 17 | 3 | 4 | 10 | 17 | 30 | -13 | 13 |
| 20 | Monza | 17 | 1 | 7 | 9 | 15 | 23 | -8 | 10 |
| > Serie A Full Table | |||||||||
