The South African-born midfielder of Scottish dissent has signed a three-year deal with The Owls after joining from Livingstone in the SPL and has an immediate dilemma to deal with regarding his international future.
O'Brien can play for both Scotland and South Africa and coaches of both national sides have had talks with the 24-year-old but at the moment, it looks as if he will end up playing for the country of his birth.
He told Footymad: "I have been approached by both Stuart Baxter of South Africa and Walter Smith of Scotland and this issue is something that has been ongoing for a while now. I understand that most likely it will be South Africa but that could change within the coming week.
"One of the things which attracted me to South Africa was the chance of playing in the World Cup next year. Stuart Baxter has almost guaranteed me a place in the squad if I am playing well enough – it’s just now getting a call up and proving that I can make the starting 11. But the main thing is looking forward to starting my career here and the international thing will take care of itself.
"It would be nice to be playing internationally as soon as possible but I have to get games under my belt here and make the squad."
South Africa are currently second in their World Cup qualifying group behind Ghana while Scotland have an uphill task to qualify as they are currently second bottom and chasing the tails of Belarus, Slovenia, Norway and Italy.