O’Brien told Sky Sports News: “I hope within the next three weeks I will be back out on the pitch and playing. The team is flying at the moment.
“It’s been a terrible time. Obviously I hope to get back into it and keep playing again and continue on to have a great end to the season.
“I’ve had a few setbacks and it has been longer than what I first thought. To get fit is the next target and then try and get in the team.”