The Leicester City defender has returned to the international fold but finds his position under threat from John O'Shea and Ciaran Clark
A hamstring injury had kept the Leicester City centre back out of action since October 2012, but he has been recalled by Giovanni Trapattoni after making a full recovery. And the Foxes player was full of praise for the Italian tactician, whom he says was 'brilliant' during the defender's layover.
"The manager [Giovanni Trapattoni] has been brilliant with me in the time that I've been out. I can't speak highly enough of him," St Ledger told reporters.
In St Ledger's absence, Aston Villa defender Ciaran Clark has stepped in to fill the void, partnering Sunderland centre back John O'Shea during the last two friendlies against Greece and Poland. As a result, St Ledger finds his position under threat.
However, the 28-year-old, who has picked up 32 caps for the Boys in Green, said that he will accept Trapattoni's team selections, stressing that he was happy simply to be involved.
"I feel fit, I've played two games in a short period of time for my club, I've had a five-month break, I'm relatively fresh, but whatever decision he makes, I'll just have to go with it," he said.
"He's been in the game long enough to make that decision. For me, it's just great to be back involved. Everyone who turns up wants to play, the main objective is to get to Rio [de Janeiro]. If it's the case that I don't play and we get there, then that's perfectly fine."
The Ireland squad has changed dramatically since Euro 2012, when St Ledger last featured, with Shay Given and Damien Duff entering retirement and Richard Dunne suffering a long-term injury problem, but the Leicester defender believes that change 'happens to the best of teams'.
"There has been a big upheaval, but change is going to happen. It happens to the best of teams," he said.
"And new players come through, like Seamus Coleman, James McCarthy, Marc Wilson, who have been brilliant. They'll be in the team for many years to come."
He continued: "Whether we qualify or not they'll benefit from the experience of this campaign and hopefully that will stand to us in the future.
"But, of course, to be missing someone like Richard [Dunne] is massive, you miss him when you're down there fighting for points. Hopefully he'll be back, the sooner he is the better."
Meanwhile, St Ledger has admitted that he does not know the exact details of his treatment with Bayern Munich club doctor, Dr Hans Wilhelm Muller Wolfhart.
"I don't know [what was injected]. Calf’s blood maybe? Not sure. I think he keeps it quiet. It did the trick anyway," said the Leicester City defender.
"It was brilliant. He was a really nice guy, really professional. The second time I went over Miroslav Klose and Arjen Robben were there, so he's obviously the best."