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 | 36 | 25 | 8 | 3 | 59 | 24 | 35 | 83 |
| 2 | Wycombe WanderersWycombe | 37 | 20 | 11 | 6 | 64 | 36 | 28 | 71 |
| 3 | Wrexham | 37 | 21 | 8 | 8 | 51 | 30 | 21 | 71 |
| 4 | Charlton AthleticCharlton | 37 | 19 | 9 | 9 | 49 | 32 | 17 | 66 |
| 5 | Stockport CountyStockport | 37 | 18 | 11 | 8 | 53 | 34 | 19 | 65 |
| 6 | Huddersfield TownHuddersfield | 37 | 18 | 7 | 12 | 52 | 34 | 18 | 61 |
| 7 | Bolton WanderersBolton | 37 | 18 | 6 | 13 | 59 | 55 | 4 | 60 |
| 8 | Reading | 37 | 16 | 11 | 10 | 52 | 46 | 6 | 59 |
| 9 | Leyton Orient | 37 | 17 | 5 | 15 | 53 | 38 | 15 | 56 |
| 10 | Barnsley | 37 | 15 | 7 | 15 | 51 | 53 | -2 | 52 |
| 11 | Blackpool | 37 | 12 | 15 | 10 | 55 | 50 | 5 | 51 |
| 12 | Lincoln CityLincoln | 37 | 13 | 10 | 14 | 53 | 45 | 8 | 49 |
| 13 | Stevenage | 37 | 13 | 10 | 14 | 35 | 38 | -3 | 49 |
| 14 | Rotherham UnitedRotherham | 37 | 12 | 9 | 16 | 42 | 45 | -3 | 45 |
| 15 | Mansfield TownMansfield | 37 | 12 | 8 | 17 | 43 | 51 | -8 | 44 |
| 16 | Exeter CityExeter | 36 | 12 | 8 | 16 | 40 | 51 | -11 | 44 |
| 17 | Wigan AthleticWigan | 36 | 11 | 10 | 15 | 33 | 36 | -3 | 43 |
| 18 | Peterborough UnitedPeterborough | 36 | 11 | 9 | 16 | 53 | 60 | -7 | 42 |
| 19 | Northampton TownNorthampton | 37 | 10 | 12 | 15 | 37 | 54 | -17 | 42 |
| 20 | Bristol Rovers | 37 | 12 | 6 | 19 | 39 | 60 | -21 | 42 |
| 21 | Burton Albion | 37 | 8 | 12 | 17 | 38 | 53 | -15 | 36 |
| 22 | Crawley TownCrawley | 37 | 7 | 9 | 21 | 39 | 71 | -32 | 30 |
| 23 | Cambridge UnitedCambridge | 37 | 7 | 8 | 22 | 35 | 61 | -26 | 29 |
| 24 | Shrewsbury TownShrewsbury | 37 | 7 | 7 | 23 | 34 | 62 | -28 | 28 |
| > League One Full Table | |||||||||
