The 37-year-old told The Sun: "People quickly forget about you when you're not playing. So it's an important time for me to try to show people I have still got the ability.
"It's a perfect platform to try and get a move in January. I will keep every option open, whatever league or country that is in. I'm not bothered.
"I have found it difficult, I really have. When you are training for months on end and not playing, of course it is difficult. The manager has been very good to me. I know people say 'he dropped you', which he did, but he's been very supportive too."
The former Republic of Ireland international kept a clean sheet on his debut for Middlesbrough last weekend.