The 24-year-old defender left Brentford earlier this summer after his contract expired, but he sufficiently impressed during training to gain a new deal.
Osborne came through the youth ranks at Griffin Park, paying 185 times after making his debut in 2005.
Millwall finished 16th in the Championship last season.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | West Bromwich AlbionWest Brom | 7 | 5 | 1 | 1 | 12 | 5 | 7 | 16 |
| 2 | Sunderland | 7 | 5 | 0 | 2 | 14 | 6 | 8 | 15 |
| 3 | Blackburn RoversBlackburn | 7 | 4 | 3 | 0 | 14 | 6 | 8 | 15 |
| 4 | Burnley | 7 | 4 | 2 | 1 | 13 | 4 | 9 | 14 |
| 5 | Leeds UnitedLeeds | 7 | 4 | 2 | 1 | 12 | 4 | 8 | 14 |
| 6 | Sheffield UnitedSheff Utd | 7 | 4 | 3 | 0 | 9 | 3 | 6 | 13 |
| 7 | Watford | 7 | 4 | 1 | 2 | 12 | 10 | 2 | 13 |
| 8 | Middlesbrough | 7 | 3 | 2 | 2 | 8 | 5 | 3 | 11 |
| 9 | Swansea CitySwansea | 7 | 3 | 2 | 2 | 8 | 5 | 3 | 11 |
| 10 | Norwich CityNorwich | 7 | 3 | 2 | 2 | 11 | 9 | 2 | 11 |
| 11 | Oxford UnitedOxford Utd | 7 | 3 | 1 | 3 | 10 | 8 | 2 | 10 |
| 12 | Hull City | 7 | 2 | 3 | 2 | 9 | 8 | 1 | 9 |
| 13 | Derby CountyDerby | 7 | 3 | 0 | 4 | 10 | 10 | 0 | 9 |
| 14 | Bristol City | 7 | 2 | 3 | 2 | 9 | 13 | -4 | 9 |
| 15 | Millwall | 7 | 2 | 2 | 3 | 12 | 10 | 2 | 8 |
| 16 | Plymouth ArgylePlymouth | 7 | 2 | 2 | 3 | 8 | 11 | -3 | 8 |
| 17 | Queens Park RangersQPR | 7 | 1 | 4 | 2 | 8 | 11 | -3 | 7 |
| 18 | Sheffield WednesdaySheff Weds | 7 | 2 | 1 | 4 | 9 | 14 | -5 | 7 |
| 19 | Luton TownLuton | 7 | 2 | 1 | 4 | 6 | 11 | -5 | 7 |
| 20 | Stoke CityStoke | 7 | 2 | 0 | 5 | 4 | 11 | -7 | 6 |
| 21 | Coventry CityCoventry | 7 | 1 | 2 | 4 | 6 | 11 | -5 | 5 |
| 22 | Preston North EndPreston | 7 | 1 | 2 | 4 | 4 | 12 | -8 | 5 |
| 23 | Portsmouth | 7 | 0 | 4 | 3 | 7 | 13 | -6 | 4 |
| 24 | Cardiff CityCardiff | 7 | 0 | 1 | 6 | 2 | 17 | -15 | 1 |
| > Championship Full Table | |||||||||
