The 21-year-old Irishman is yet to make a senior appearance for Rovers since graduating from the club's youth academy in 2011.
O'Connor spent part of last season on loan at Torquay United, where he was sent off in his final game for the club.
The youngster's overhanging suspension means that he will miss Plymouth's League Two opener away to Cambridge United on Saturday.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Sunderland | 15 | 9 | 4 | 2 | 25 | 11 | 14 | 31 |
| 2 | Sheffield UnitedSheff Utd | 15 | 10 | 3 | 2 | 19 | 7 | 12 | 31 |
| 3 | Leeds UnitedLeeds | 15 | 8 | 5 | 2 | 24 | 9 | 15 | 29 |
| 4 | Burnley | 15 | 7 | 6 | 2 | 18 | 6 | 12 | 27 |
| 5 | West Bromwich AlbionWest Brom | 15 | 6 | 7 | 2 | 16 | 9 | 7 | 25 |
| 6 | Watford | 15 | 8 | 1 | 6 | 23 | 22 | 1 | 25 |
| 7 | Middlesbrough | 15 | 7 | 3 | 5 | 23 | 17 | 6 | 24 |
| 8 | Millwall | 15 | 6 | 5 | 4 | 18 | 13 | 5 | 23 |
| 9 | Blackburn RoversBlackburn | 15 | 6 | 4 | 5 | 19 | 17 | 2 | 22 |
| 10 | Bristol City | 15 | 5 | 7 | 3 | 20 | 19 | 1 | 22 |
| 11 | Swansea CitySwansea | 15 | 5 | 4 | 6 | 11 | 10 | 1 | 19 |
| 12 | Derby CountyDerby | 15 | 5 | 4 | 6 | 19 | 19 | 0 | 19 |
| 13 | Stoke CityStoke | 15 | 5 | 4 | 6 | 18 | 19 | -1 | 19 |
| 14 | Norwich CityNorwich | 15 | 4 | 6 | 5 | 23 | 22 | 1 | 18 |
| 15 | Sheffield WednesdaySheff Weds | 15 | 5 | 3 | 7 | 17 | 25 | -8 | 18 |
| 16 | Oxford UnitedOxford Utd | 15 | 4 | 5 | 6 | 17 | 18 | -1 | 17 |
| 17 | Coventry CityCoventry | 15 | 4 | 4 | 7 | 20 | 21 | -1 | 16 |
| 18 | Plymouth ArgylePlymouth | 15 | 4 | 4 | 7 | 15 | 26 | -11 | 16 |
| 19 | Hull City | 15 | 3 | 6 | 6 | 16 | 20 | -4 | 15 |
| 20 | Preston North EndPreston | 15 | 3 | 6 | 6 | 15 | 23 | -8 | 15 |
| 21 | Luton TownLuton | 15 | 4 | 3 | 8 | 17 | 26 | -9 | 15 |
| 22 | Cardiff CityCardiff | 15 | 4 | 3 | 8 | 14 | 23 | -9 | 15 |
| 23 | Portsmouth | 15 | 2 | 6 | 7 | 16 | 28 | -12 | 12 |
| 24 | Queens Park RangersQPR | 15 | 1 | 7 | 7 | 12 | 25 | -13 | 10 |
| > Championship Full Table | |||||||||
