The 32-year-old was on a season-long loan at Vicarage Road from Guangzhou Evergrande, but struggled to make an impact under Quique Flores.
The former West Ham midfielder made only three substitute appearances during his time with the Hornets.
Atalanta said that Diamanti would wear the No.23 shirt at the Stadio Atleti Azzurri d'Italia.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Leeds UnitedLeeds | 31 | 19 | 9 | 3 | 62 | 19 | 43 | 66 |
| 2 | Burnley | 31 | 16 | 13 | 2 | 37 | 9 | 28 | 61 |
| 3 | Sheffield UnitedSheff Utd | 30 | 19 | 6 | 5 | 41 | 21 | 20 | 61 |
| 4 | Sunderland | 30 | 16 | 10 | 4 | 45 | 26 | 19 | 58 |
| 5 | Blackburn RoversBlackburn | 31 | 13 | 6 | 12 | 35 | 31 | 4 | 45 |
| 6 | West Bromwich AlbionWest Brom | 30 | 10 | 14 | 6 | 39 | 27 | 12 | 44 |
| 7 | Middlesbrough | 30 | 12 | 8 | 10 | 49 | 39 | 10 | 44 |
| 8 | Norwich CityNorwich | 30 | 11 | 9 | 10 | 49 | 42 | 7 | 42 |
| 9 | Bristol City | 30 | 10 | 12 | 8 | 38 | 35 | 3 | 42 |
| 10 | Sheffield WednesdaySheff Weds | 30 | 11 | 9 | 10 | 43 | 46 | -3 | 42 |
| 11 | Coventry CityCoventry | 31 | 11 | 8 | 12 | 41 | 40 | 1 | 41 |
| 12 | Watford | 30 | 12 | 5 | 13 | 40 | 42 | -2 | 41 |
| 13 | Queens Park RangersQPR | 31 | 10 | 11 | 10 | 35 | 40 | -5 | 41 |
| 14 | Millwall | 30 | 10 | 10 | 10 | 30 | 27 | 3 | 40 |
| 15 | Preston North EndPreston | 30 | 8 | 13 | 9 | 33 | 38 | -5 | 37 |
| 16 | Oxford UnitedOxford Utd | 31 | 9 | 10 | 12 | 34 | 45 | -11 | 37 |
| 17 | Swansea CitySwansea | 30 | 9 | 7 | 14 | 32 | 42 | -10 | 34 |
| 18 | Stoke CityStoke | 30 | 7 | 11 | 12 | 28 | 37 | -9 | 32 |
| 19 | Cardiff CityCardiff | 30 | 7 | 10 | 13 | 33 | 51 | -18 | 31 |
| 20 | Portsmouth | 30 | 7 | 9 | 14 | 36 | 52 | -16 | 30 |
| 21 | Hull City | 30 | 7 | 8 | 15 | 31 | 40 | -9 | 29 |
| 22 | Derby CountyDerby | 30 | 7 | 6 | 17 | 32 | 41 | -9 | 27 |
| 23 | Luton TownLuton | 30 | 7 | 6 | 17 | 30 | 49 | -19 | 27 |
| 24 | Plymouth ArgylePlymouth | 30 | 5 | 10 | 15 | 29 | 63 | -34 | 25 |
| > Championship Full Table | |||||||||
