The 27-year-old strained a medial ligament in his knee in a friendly match against Burton.
The Republic of Ireland international will now miss the opening weeks of the season as well as an international friendly against Serbia.
Joey O'Brien of West Ham United has been called up as cover for St Ledger by Republic of Ireland manager Giovanni Trapattoni.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Liverpool | 10 | 8 | 1 | 1 | 19 | 6 | 13 | 25 |
| 2 | Manchester CityMan City | 10 | 7 | 2 | 1 | 21 | 11 | 10 | 23 |
| 3 | Nottingham ForestNott'm Forest | 10 | 5 | 4 | 1 | 14 | 7 | 7 | 19 |
| 4 | Chelsea | 10 | 5 | 3 | 2 | 20 | 12 | 8 | 18 |
| 5 | Arsenal | 10 | 5 | 3 | 2 | 17 | 11 | 6 | 18 |
| 6 | Aston Villa | 10 | 5 | 3 | 2 | 17 | 15 | 2 | 18 |
| 7 | Tottenham HotspurSpurs | 10 | 5 | 1 | 4 | 22 | 11 | 11 | 16 |
| 8 | Brighton & Hove AlbionBrighton | 10 | 4 | 4 | 2 | 17 | 14 | 3 | 16 |
| 9 | Fulham | 10 | 4 | 3 | 3 | 14 | 13 | 1 | 15 |
| 10 | Bournemouth | 10 | 4 | 3 | 3 | 13 | 12 | 1 | 15 |
| 11 | Newcastle UnitedNewcastle | 10 | 4 | 3 | 3 | 10 | 10 | 0 | 15 |
| 12 | Brentford | 10 | 4 | 1 | 5 | 19 | 20 | -1 | 13 |
| 13 | Manchester UnitedMan Utd | 10 | 3 | 3 | 4 | 9 | 12 | -3 | 12 |
| 14 | West Ham UnitedWest Ham | 10 | 3 | 2 | 5 | 13 | 19 | -6 | 11 |
| 15 | Leicester CityLeicester | 10 | 2 | 4 | 4 | 14 | 18 | -4 | 10 |
| 16 | Everton | 10 | 2 | 3 | 5 | 10 | 17 | -7 | 9 |
| 17 | Crystal Palace | 10 | 1 | 4 | 5 | 8 | 13 | -5 | 7 |
| 18 | Ipswich TownIpswich | 10 | 0 | 5 | 5 | 10 | 21 | -11 | 5 |
| 19 | Southampton | 10 | 1 | 1 | 8 | 7 | 19 | -12 | 4 |
| 20 | Wolverhampton WanderersWolves | 10 | 0 | 3 | 7 | 14 | 27 | -13 | 3 |
| > Premier League Full Table | |||||||||
