The 22-year-old arrived at Meadow Lane from Huddersfield Town in February on a short-term deal until the end of the season.
However, Spencer's fresh terms are due to expire at the end of the 2015-16 campaign.
The forward scored five goals in 13 games for County last season as they narrowly avoided relegation to League Two.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Port Vale | 16 | 10 | 3 | 3 | 24 | 16 | 8 | 33 |
| 2 | Crewe AlexandraCrewe | 15 | 8 | 4 | 3 | 19 | 13 | 6 | 28 |
| 3 | Doncaster RoversDoncaster | 16 | 8 | 4 | 4 | 22 | 18 | 4 | 28 |
| 4 | Walsall | 14 | 8 | 3 | 3 | 27 | 15 | 12 | 27 |
| 5 | MK Dons | 16 | 8 | 3 | 5 | 27 | 19 | 8 | 27 |
| 6 | Notts County | 16 | 7 | 6 | 3 | 23 | 15 | 8 | 27 |
| 7 | Grimsby Town | 16 | 8 | 1 | 7 | 19 | 25 | -6 | 25 |
| 8 | Bradford CityBradford | 16 | 6 | 5 | 5 | 21 | 17 | 4 | 23 |
| 9 | Gillingham | 15 | 7 | 2 | 6 | 16 | 12 | 4 | 23 |
| 10 | AFC Wimbledon | 13 | 7 | 1 | 5 | 21 | 11 | 10 | 22 |
| 11 | Chesterfield | 16 | 5 | 7 | 4 | 29 | 20 | 9 | 22 |
| 12 | BarrowBarrow | 16 | 6 | 4 | 6 | 17 | 15 | 2 | 22 |
| 13 | Fleetwood TownFleetwood | 14 | 5 | 6 | 3 | 20 | 15 | 5 | 21 |
| 14 | Salford City | 16 | 5 | 6 | 5 | 15 | 18 | -3 | 21 |
| 15 | Newport CountyNewport | 16 | 6 | 2 | 8 | 19 | 26 | -7 | 20 |
| 16 | Cheltenham TownCheltenham | 16 | 5 | 3 | 8 | 21 | 25 | -4 | 18 |
| 17 | Harrogate TownHarrogate | 16 | 5 | 3 | 8 | 14 | 22 | -8 | 18 |
| 18 | Accrington StanleyAccrington | 15 | 4 | 5 | 6 | 20 | 24 | -4 | 17 |
| 19 | Tranmere RoversTranmere | 14 | 4 | 5 | 5 | 10 | 17 | -7 | 17 |
| 20 | Bromley | 15 | 3 | 7 | 5 | 17 | 19 | -2 | 16 |
| 21 | Colchester UnitedColchester | 15 | 2 | 8 | 5 | 18 | 22 | -4 | 14 |
| 22 | Swindon TownSwindon | 16 | 2 | 7 | 7 | 18 | 25 | -7 | 13 |
| 23 | Carlisle UnitedCarlisle | 16 | 3 | 3 | 10 | 14 | 29 | -15 | 12 |
| 24 | Morecambe | 16 | 2 | 4 | 10 | 14 | 27 | -13 | 10 |
| > League Two Full Table | |||||||||
