The deal runs until January 2 and does not include a clause allowing Birmingham to recall the 29-year-old, who is in the last year of his contract at St Andrew's.
Duffy joined Birmingham from Doncaster Rovers a year ago, but made just one Championship start in his debut campaign.
He also had a brief loan spell in League One with Chesterfield in February earlier this year.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Birmingham CityBirmingham | 8 | 7 | 1 | 0 | 17 | 8 | 9 | 22 |
| 2 | Wrexham | 9 | 5 | 2 | 2 | 14 | 7 | 7 | 17 |
| 3 | Mansfield TownMansfield | 8 | 5 | 2 | 1 | 15 | 11 | 4 | 17 |
| 4 | Stockport CountyStockport | 8 | 4 | 3 | 1 | 13 | 7 | 6 | 15 |
| 5 | Lincoln CityLincoln | 8 | 4 | 3 | 1 | 13 | 7 | 6 | 15 |
| 6 | Blackpool | 9 | 4 | 3 | 2 | 17 | 14 | 3 | 15 |
| 7 | Barnsley | 9 | 4 | 3 | 2 | 15 | 13 | 2 | 15 |
| 8 | Wycombe WanderersWycombe | 8 | 4 | 2 | 2 | 16 | 13 | 3 | 14 |
| 9 | Stevenage | 9 | 4 | 2 | 3 | 7 | 5 | 2 | 14 |
| 10 | Exeter CityExeter | 8 | 4 | 1 | 3 | 9 | 6 | 3 | 13 |
| 11 | Bolton WanderersBolton | 8 | 4 | 1 | 3 | 13 | 13 | 0 | 13 |
| 12 | Reading | 8 | 4 | 1 | 3 | 12 | 12 | 0 | 13 |
| 13 | Charlton AthleticCharlton | 9 | 4 | 1 | 4 | 9 | 9 | 0 | 13 |
| 14 | Wigan AthleticWigan | 9 | 3 | 3 | 3 | 9 | 5 | 4 | 12 |
| 15 | Huddersfield TownHuddersfield | 9 | 4 | 0 | 5 | 12 | 11 | 1 | 12 |
| 16 | Peterborough UnitedPeterborough | 9 | 3 | 2 | 4 | 14 | 17 | -3 | 11 |
| 17 | Rotherham UnitedRotherham | 9 | 2 | 4 | 3 | 7 | 10 | -3 | 10 |
| 18 | Bristol Rovers | 9 | 3 | 1 | 5 | 10 | 15 | -5 | 10 |
| 19 | Northampton TownNorthampton | 8 | 2 | 2 | 4 | 10 | 13 | -3 | 8 |
| 20 | Leyton Orient | 9 | 2 | 2 | 5 | 9 | 12 | -3 | 8 |
| 21 | Crawley TownCrawley | 8 | 2 | 1 | 5 | 5 | 12 | -7 | 7 |
| 22 | Burton Albion | 8 | 0 | 4 | 4 | 9 | 16 | -7 | 4 |
| 23 | Shrewsbury TownShrewsbury | 9 | 1 | 1 | 7 | 6 | 15 | -9 | 4 |
| 24 | Cambridge UnitedCambridge | 8 | 0 | 1 | 7 | 6 | 16 | -10 | 1 |
| > League One Full Table | |||||||||
