The 29-year-old had been on loan at the League Two club since November.
Harley, who spent just six months at Swindon, enjoyed a four-year spell with Exeter between 2007 and 2011.
City continue their league campaign on Saturday with a trip to Mansfield Town.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Birmingham CityBirmingham | 7 | 6 | 1 | 0 | 16 | 8 | 8 | 19 |
| 2 | Wrexham | 8 | 5 | 2 | 1 | 14 | 6 | 8 | 17 |
| 3 | Lincoln CityLincoln | 7 | 4 | 2 | 1 | 12 | 6 | 6 | 14 |
| 4 | Blackpool | 8 | 4 | 2 | 2 | 16 | 13 | 3 | 14 |
| 5 | Mansfield TownMansfield | 7 | 4 | 2 | 1 | 13 | 11 | 2 | 14 |
| 6 | Barnsley | 8 | 4 | 2 | 2 | 13 | 11 | 2 | 14 |
| 7 | Wycombe WanderersWycombe | 7 | 4 | 1 | 2 | 14 | 11 | 3 | 13 |
| 8 | Charlton AthleticCharlton | 8 | 4 | 1 | 3 | 7 | 6 | 1 | 13 |
| 9 | Stockport CountyStockport | 7 | 3 | 3 | 1 | 11 | 7 | 4 | 12 |
| 10 | Huddersfield TownHuddersfield | 8 | 4 | 0 | 4 | 12 | 10 | 2 | 12 |
| 11 | Stevenage | 8 | 3 | 2 | 3 | 6 | 5 | 1 | 11 |
| 12 | Peterborough UnitedPeterborough | 8 | 3 | 2 | 3 | 14 | 14 | 0 | 11 |
| 13 | Exeter CityExeter | 7 | 3 | 1 | 3 | 8 | 6 | 2 | 10 |
| 14 | Bolton WanderersBolton | 7 | 3 | 1 | 3 | 9 | 11 | -2 | 10 |
| 15 | Reading | 7 | 3 | 1 | 3 | 9 | 11 | -2 | 10 |
| 16 | Wigan AthleticWigan | 8 | 2 | 3 | 3 | 6 | 5 | 1 | 9 |
| 17 | Northampton TownNorthampton | 7 | 2 | 2 | 3 | 8 | 9 | -1 | 8 |
| 18 | Leyton Orient | 8 | 2 | 2 | 4 | 9 | 11 | -2 | 8 |
| 19 | Rotherham UnitedRotherham | 8 | 1 | 4 | 3 | 6 | 10 | -4 | 7 |
| 20 | Crawley TownCrawley | 7 | 2 | 1 | 4 | 5 | 10 | -5 | 7 |
| 21 | Bristol Rovers | 8 | 2 | 1 | 5 | 7 | 13 | -6 | 7 |
| 22 | Burton Albion | 7 | 0 | 4 | 3 | 8 | 13 | -5 | 4 |
| 23 | Shrewsbury TownShrewsbury | 8 | 1 | 1 | 6 | 6 | 13 | -7 | 4 |
| 24 | Cambridge UnitedCambridge | 7 | 0 | 1 | 6 | 6 | 15 | -9 | 1 |
| > League One Full Table | |||||||||
