The Ireland international has been out of action since October after tearing his hamstring and has found it difficult to overcome the injury
As a result, the 27-year-old centre back may be forced to undergo surgery in order to correct the issue, casting doubts over his potential involvement in the Republic of Ireland's upcoming World Cup qualifying games in March 2013.
"It has been a bit longer than I anticipated," St Ledger told reporters. "I'm still not cured or sure what the problem is so it could be a while yet."
He continued: "It is the same injury that ruled me out of the Germany game. I've attempted to go back training a couple of times, but there has been bleeding on the muscle. That has stayed there.
"I don't think it was ever going to be easy. It was a grade two (tear), so I knew it would be long, but I never anticipated it would take this long."
Should the former Preston North End defender endure surgery, he will certainly be out for a period of two months and St Ledger admitted that it is 'the last thing [he wants]'.
He said: "I'm just going in each day and taking it easily, I might be going to Germany for a second opinion. The last option is to have surgery and have it drained, but that's two months out and it's the last thing I want.
"It is a pretty rare condition and the medics have said they haven't seen too many people with this kind of injury. It is not something simple as hamstrings usually are. It is more complicated," added the defender.