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 | Sheffield UnitedSheff Utd | 22 | 15 | 5 | 2 | 32 | 11 | 21 | 48 |
| 2 | Leeds UnitedLeeds | 22 | 13 | 6 | 3 | 41 | 15 | 26 | 45 |
| 3 | Burnley | 22 | 12 | 8 | 2 | 28 | 9 | 19 | 44 |
| 4 | Sunderland | 22 | 12 | 7 | 3 | 34 | 18 | 16 | 43 |
| 5 | Blackburn RoversBlackburn | 21 | 11 | 4 | 6 | 25 | 18 | 7 | 37 |
| 6 | Middlesbrough | 22 | 10 | 5 | 7 | 38 | 28 | 10 | 35 |
| 7 | West Bromwich AlbionWest Brom | 22 | 8 | 11 | 3 | 26 | 16 | 10 | 35 |
| 8 | Watford | 21 | 10 | 4 | 7 | 30 | 28 | 2 | 34 |
| 9 | Sheffield WednesdaySheff Weds | 22 | 9 | 5 | 8 | 28 | 30 | -2 | 32 |
| 10 | Millwall | 21 | 7 | 7 | 7 | 21 | 18 | 3 | 28 |
| 11 | Swansea CitySwansea | 22 | 7 | 6 | 9 | 24 | 24 | 0 | 27 |
| 12 | Bristol City | 22 | 6 | 9 | 7 | 26 | 28 | -2 | 27 |
| 13 | Norwich CityNorwich | 22 | 6 | 8 | 8 | 37 | 34 | 3 | 26 |
| 14 | Queens Park RangersQPR | 22 | 5 | 10 | 7 | 23 | 28 | -5 | 25 |
| 15 | Luton TownLuton | 22 | 7 | 4 | 11 | 25 | 38 | -13 | 25 |
| 16 | Derby CountyDerby | 22 | 6 | 6 | 10 | 27 | 28 | -1 | 24 |
| 17 | Coventry CityCoventry | 22 | 6 | 6 | 10 | 28 | 34 | -6 | 24 |
| 18 | Preston North EndPreston | 22 | 4 | 11 | 7 | 22 | 29 | -7 | 23 |
| 19 | Stoke CityStoke | 22 | 5 | 7 | 10 | 23 | 30 | -7 | 22 |
| 20 | Portsmouth | 20 | 4 | 8 | 8 | 25 | 35 | -10 | 20 |
| 21 | Hull City | 22 | 4 | 7 | 11 | 21 | 31 | -10 | 19 |
| 22 | Cardiff CityCardiff | 21 | 4 | 6 | 11 | 19 | 34 | -15 | 18 |
| 23 | Oxford UnitedOxford Utd | 21 | 4 | 6 | 11 | 21 | 37 | -16 | 18 |
| 24 | Plymouth ArgylePlymouth | 21 | 4 | 6 | 11 | 22 | 45 | -23 | 18 |
| > Championship Full Table | |||||||||
