The centre-back arrived at the Keepmoat Stadium back in October on loan from League One rivals Sheffield United.
However, with that deal due to expire in the near future, the 31-year-old has agreed terms on a contract that will expire in the summer of 2016.
Butler has made 13 appearances for Rovers this term, scoring one goal.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Walsall | 18 | 11 | 4 | 3 | 34 | 19 | 15 | 37 |
| 2 | Port Vale | 19 | 10 | 5 | 4 | 26 | 19 | 7 | 35 |
| 3 | Doncaster RoversDoncaster | 19 | 9 | 6 | 4 | 28 | 22 | 6 | 33 |
| 4 | Crewe AlexandraCrewe | 18 | 8 | 7 | 3 | 22 | 16 | 6 | 31 |
| 5 | Grimsby Town | 19 | 10 | 1 | 8 | 27 | 28 | -1 | 31 |
| 6 | AFC Wimbledon | 18 | 9 | 3 | 6 | 30 | 16 | 14 | 30 |
| 7 | MK Dons | 17 | 9 | 3 | 5 | 30 | 19 | 11 | 30 |
| 8 | Chesterfield | 19 | 7 | 7 | 5 | 33 | 23 | 10 | 28 |
| 9 | Notts County | 18 | 7 | 7 | 4 | 25 | 18 | 7 | 28 |
| 10 | Gillingham | 18 | 8 | 2 | 8 | 19 | 16 | 3 | 26 |
| 11 | Bradford CityBradford | 18 | 6 | 7 | 5 | 23 | 19 | 4 | 25 |
| 12 | Salford City | 18 | 6 | 6 | 6 | 17 | 19 | -2 | 24 |
| 13 | BarrowBarrow | 18 | 6 | 5 | 7 | 18 | 17 | 1 | 23 |
| 14 | Bromley | 18 | 5 | 8 | 5 | 23 | 23 | 0 | 23 |
| 15 | Cheltenham TownCheltenham | 19 | 6 | 5 | 8 | 25 | 28 | -3 | 23 |
| 16 | Fleetwood TownFleetwood | 17 | 5 | 7 | 5 | 23 | 22 | 1 | 22 |
| 17 | Newport CountyNewport | 18 | 6 | 4 | 8 | 21 | 28 | -7 | 22 |
| 18 | Colchester UnitedColchester | 18 | 4 | 9 | 5 | 23 | 22 | 1 | 21 |
| 19 | Harrogate TownHarrogate | 19 | 6 | 3 | 10 | 16 | 28 | -12 | 21 |
| 20 | Accrington StanleyAccrington | 18 | 4 | 6 | 8 | 25 | 33 | -8 | 18 |
| 21 | Tranmere RoversTranmere | 18 | 4 | 6 | 8 | 12 | 25 | -13 | 18 |
| 22 | Swindon TownSwindon | 19 | 3 | 7 | 9 | 23 | 33 | -10 | 16 |
| 23 | Morecambe | 19 | 3 | 5 | 11 | 19 | 34 | -15 | 14 |
| 24 | Carlisle UnitedCarlisle | 18 | 3 | 5 | 10 | 15 | 30 | -15 | 14 |
| > League Two Full Table | |||||||||
