The 28-year-old Republic of Ireland international will meet up with his new teammates after their Championship fixture against Leicester on Friday.
He has been cleared to play in Millwall's FA Cup semi-final against Wigan Athletic next month.
St Ledger had made 10 appearances in all competitions this season before his short-term deal was agreed.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Sheffield UnitedSheff Utd | 20 | 13 | 5 | 2 | 28 | 11 | 17 | 42 |
| 2 | Leeds UnitedLeeds | 20 | 12 | 5 | 3 | 36 | 14 | 22 | 41 |
| 3 | Burnley | 20 | 10 | 8 | 2 | 24 | 7 | 17 | 38 |
| 4 | Sunderland | 20 | 10 | 7 | 3 | 29 | 15 | 14 | 37 |
| 5 | Blackburn RoversBlackburn | 19 | 10 | 4 | 5 | 23 | 17 | 6 | 34 |
| 6 | West Bromwich AlbionWest Brom | 20 | 7 | 11 | 2 | 23 | 14 | 9 | 32 |
| 7 | Middlesbrough | 20 | 9 | 4 | 7 | 34 | 25 | 9 | 31 |
| 8 | Watford | 19 | 9 | 4 | 6 | 27 | 25 | 2 | 31 |
| 9 | Swansea CitySwansea | 20 | 7 | 6 | 7 | 21 | 19 | 2 | 27 |
| 10 | Norwich CityNorwich | 20 | 6 | 8 | 6 | 35 | 30 | 5 | 26 |
| 11 | Bristol City | 20 | 6 | 8 | 6 | 25 | 25 | 0 | 26 |
| 12 | Sheffield WednesdaySheff Weds | 20 | 7 | 5 | 8 | 23 | 29 | -6 | 26 |
| 13 | Millwall | 19 | 6 | 7 | 6 | 20 | 17 | 3 | 25 |
| 14 | Preston North EndPreston | 20 | 4 | 10 | 6 | 20 | 26 | -6 | 22 |
| 15 | Luton TownLuton | 20 | 6 | 4 | 10 | 23 | 35 | -12 | 22 |
| 16 | Coventry CityCoventry | 20 | 5 | 6 | 9 | 25 | 29 | -4 | 21 |
| 17 | Derby CountyDerby | 20 | 5 | 6 | 9 | 22 | 26 | -4 | 21 |
| 18 | Stoke CityStoke | 20 | 5 | 6 | 9 | 21 | 26 | -5 | 21 |
| 19 | Queens Park RangersQPR | 20 | 4 | 9 | 7 | 20 | 26 | -6 | 21 |
| 20 | Oxford UnitedOxford Utd | 19 | 4 | 6 | 9 | 20 | 30 | -10 | 18 |
| 21 | Portsmouth | 18 | 3 | 8 | 7 | 21 | 30 | -9 | 17 |
| 22 | Cardiff CityCardiff | 19 | 4 | 5 | 10 | 17 | 30 | -13 | 17 |
| 23 | Plymouth ArgylePlymouth | 19 | 4 | 5 | 10 | 19 | 40 | -21 | 17 |
| 24 | Hull City | 20 | 3 | 7 | 10 | 18 | 28 | -10 | 16 |
| > Championship Full Table | |||||||||
