The 35-year old Republic of Ireland international has fallen to number two behind Joe Hart at City and insists that he simply wants to be playing football.
And although he is a massive fan of Glasgow Celtic, the club where he kicked off his career, he says that there is nothing concrete about rumours of a return.
"I said last week when I was away with Ireland that it's a fantastic club, with great history and great supporters," he told Sky Sports News from a coaching course in Ireland.
"But it's purely speculation at the minute, I don't really know about it.
"(Celtic assistant manager) Alan Thompson's on this course as well so he's been giving me a bit of ear-ache.
"It's too early to say but it is a fantastic club."