The 28-year-old's deal with the League One club is due to expire on January 13.
He arrives at Ashton Gate having previously worked under City boss Sean O'Driscoll at Bournemouth and Doncaster Rovers.
O'Connor joined Derby from Doncaster last summer on a two-year contract with the option of a further 12 months.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Sunderland | 14 | 9 | 3 | 2 | 23 | 9 | 14 | 30 |
| 2 | Sheffield UnitedSheff Utd | 14 | 9 | 3 | 2 | 18 | 7 | 11 | 28 |
| 3 | Leeds UnitedLeeds | 14 | 7 | 5 | 2 | 22 | 9 | 13 | 26 |
| 4 | Burnley | 14 | 6 | 6 | 2 | 17 | 6 | 11 | 24 |
| 5 | West Bromwich AlbionWest Brom | 14 | 5 | 7 | 2 | 14 | 8 | 6 | 22 |
| 6 | Millwall | 14 | 6 | 4 | 4 | 17 | 12 | 5 | 22 |
| 7 | Watford | 14 | 7 | 1 | 6 | 22 | 22 | 0 | 22 |
| 8 | Middlesbrough | 14 | 6 | 3 | 5 | 18 | 16 | 2 | 21 |
| 9 | Swansea CitySwansea | 14 | 5 | 4 | 5 | 11 | 9 | 2 | 19 |
| 10 | Blackburn RoversBlackburn | 14 | 5 | 4 | 5 | 16 | 16 | 0 | 19 |
| 11 | Bristol City | 14 | 4 | 7 | 3 | 18 | 19 | -1 | 19 |
| 12 | Norwich CityNorwich | 14 | 4 | 6 | 4 | 23 | 20 | 3 | 18 |
| 13 | Derby CountyDerby | 14 | 5 | 3 | 6 | 18 | 18 | 0 | 18 |
| 14 | Stoke CityStoke | 14 | 5 | 3 | 6 | 17 | 18 | -1 | 18 |
| 15 | Sheffield WednesdaySheff Weds | 14 | 5 | 3 | 6 | 17 | 24 | -7 | 18 |
| 16 | Oxford UnitedOxford Utd | 14 | 4 | 5 | 5 | 17 | 17 | 0 | 17 |
| 17 | Coventry CityCoventry | 14 | 4 | 3 | 7 | 18 | 19 | -1 | 15 |
| 18 | Hull City | 14 | 3 | 6 | 5 | 15 | 18 | -3 | 15 |
| 19 | Luton TownLuton | 14 | 4 | 3 | 7 | 16 | 21 | -5 | 15 |
| 20 | Preston North EndPreston | 14 | 3 | 6 | 5 | 14 | 20 | -6 | 15 |
| 21 | Cardiff CityCardiff | 14 | 4 | 3 | 7 | 13 | 20 | -7 | 15 |
| 22 | Plymouth ArgylePlymouth | 14 | 4 | 3 | 7 | 14 | 25 | -11 | 15 |
| 23 | Queens Park RangersQPR | 14 | 1 | 7 | 6 | 12 | 23 | -11 | 10 |
| 24 | Portsmouth | 14 | 1 | 6 | 7 | 13 | 27 | -14 | 9 |
| > Championship Full Table | |||||||||
