The Republic of Ireland international suffered a detached ligament in November's victory over Wolves and was expected to miss up to two months, but could now return earlier.
He told the club's official website: "I feel good, I'm progressing day by day and hopefully it won't be too much longer.
"I've been away for a week and a bit of warm weather has helped me. I'm not on crutches any more or using the air cast boot - I'm walking around pain-free.
"I'm quite fortunate in so much that I seem to recover from injuries pretty quickly but I know I need to get my ankle right before I really push on.
"It's a case of so far so good but I don't want to rush things and jeopardise the way things have gone."