The defender spent a month on loan at the League Two side earlier in the season.
The 21-year-old has signed a three-and-a-half-year contract with the club for an undisclosed fee.
Cooper has previously had loan spells with Carlisle and Huddersfield.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Walsall | 20 | 13 | 4 | 3 | 37 | 19 | 18 | 43 |
| 2 | Port Vale | 21 | 10 | 7 | 4 | 26 | 19 | 7 | 37 |
| 3 | Doncaster RoversDoncaster | 21 | 10 | 6 | 5 | 31 | 24 | 7 | 36 |
| 4 | Crewe AlexandraCrewe | 20 | 9 | 8 | 3 | 24 | 16 | 8 | 35 |
| 5 | Chesterfield | 21 | 9 | 7 | 5 | 36 | 23 | 13 | 34 |
| 6 | AFC Wimbledon | 20 | 10 | 3 | 7 | 31 | 17 | 14 | 33 |
| 7 | Notts County | 20 | 8 | 7 | 5 | 28 | 21 | 7 | 31 |
| 8 | Grimsby Town | 21 | 10 | 1 | 10 | 28 | 33 | -5 | 31 |
| 9 | MK Dons | 19 | 9 | 3 | 7 | 33 | 26 | 7 | 30 |
| 10 | Gillingham | 20 | 9 | 3 | 8 | 22 | 18 | 4 | 30 |
| 11 | Salford City | 20 | 8 | 6 | 6 | 22 | 19 | 3 | 30 |
| 12 | Bradford CityBradford | 20 | 7 | 7 | 6 | 24 | 22 | 2 | 28 |
| 13 | Bromley | 20 | 6 | 9 | 5 | 25 | 23 | 2 | 27 |
| 14 | Cheltenham TownCheltenham | 21 | 7 | 6 | 8 | 29 | 30 | -1 | 27 |
| 15 | BarrowBarrow | 20 | 7 | 5 | 8 | 20 | 18 | 2 | 26 |
| 16 | Newport CountyNewport | 20 | 7 | 5 | 8 | 27 | 31 | -4 | 26 |
| 17 | Colchester UnitedColchester | 20 | 4 | 11 | 5 | 23 | 22 | 1 | 23 |
| 18 | Fleetwood TownFleetwood | 19 | 5 | 8 | 6 | 24 | 25 | -1 | 23 |
| 19 | Tranmere RoversTranmere | 20 | 5 | 6 | 9 | 15 | 29 | -14 | 21 |
| 20 | Harrogate TownHarrogate | 21 | 6 | 3 | 12 | 17 | 32 | -15 | 21 |
| 21 | Swindon TownSwindon | 21 | 4 | 7 | 10 | 26 | 35 | -9 | 19 |
| 22 | Accrington StanleyAccrington | 20 | 4 | 7 | 9 | 26 | 36 | -10 | 19 |
| 23 | Carlisle UnitedCarlisle | 20 | 3 | 6 | 11 | 15 | 32 | -17 | 15 |
| 24 | Morecambe | 21 | 3 | 5 | 13 | 19 | 38 | -19 | 14 |
| > League Two Full Table | |||||||||
