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 | Inter Milan | 28 | 18 | 7 | 3 | 63 | 27 | 36 | 61 |
| 2 | Napoli | 28 | 18 | 6 | 4 | 45 | 23 | 22 | 60 |
| 3 | Atalanta BCAtalanta | 28 | 17 | 7 | 4 | 63 | 26 | 37 | 58 |
| 4 | Juventus | 28 | 13 | 13 | 2 | 45 | 25 | 20 | 52 |
| 5 | Lazio | 28 | 15 | 6 | 7 | 50 | 36 | 14 | 51 |
| 6 | Bologna | 28 | 13 | 11 | 4 | 44 | 34 | 10 | 50 |
| 7 | Roma | 28 | 13 | 7 | 8 | 43 | 30 | 13 | 46 |
| 8 | Fiorentina | 28 | 13 | 6 | 9 | 43 | 30 | 13 | 45 |
| 9 | AC Milan | 28 | 12 | 8 | 8 | 42 | 32 | 10 | 44 |
| 10 | Udinese | 28 | 11 | 7 | 10 | 35 | 38 | -3 | 40 |
| 11 | Torino | 28 | 8 | 11 | 9 | 33 | 34 | -1 | 35 |
| 12 | Genoa | 28 | 7 | 11 | 10 | 26 | 36 | -10 | 32 |
| 13 | Como | 28 | 7 | 8 | 13 | 34 | 44 | -10 | 29 |
| 14 | CagliariCagliari | 28 | 6 | 8 | 14 | 28 | 43 | -15 | 26 |
| 15 | Hellas VeronaHellas Verona | 28 | 8 | 2 | 18 | 28 | 58 | -30 | 26 |
| 16 | Lecce | 28 | 6 | 7 | 15 | 20 | 46 | -26 | 25 |
| 17 | Parma | 28 | 5 | 9 | 14 | 34 | 48 | -14 | 24 |
| 18 | Empoli | 28 | 4 | 10 | 14 | 23 | 45 | -22 | 22 |
| 19 | VeneziaVenezia | 28 | 3 | 10 | 15 | 23 | 42 | -19 | 19 |
| 20 | Monza | 28 | 2 | 8 | 18 | 23 | 48 | -25 | 14 |
| > Serie A Full Table | |||||||||
