Craig Gordon admits he may have to quit Sunderland Football Club.

The £9million signing from Hearts in 2007 has lost his place to Marton Fulop in recent weeks, and as a result he was left out of Scotland’s side for their World Cup qualifier on Saturday.

"It is the first time this has happened in my career. It is very difficult to be patient. There is frustration and anger. It is horrible just sitting there,” Gordon told the News of the World.

"It's not about ego. If your ability makes you the best, if your technique is the best, then you should be playing. I am still very confident that I can be the No.1.

"But it has been a very difficult thing to face up to. I have sat in bed some nights until two or three in the morning not being able to sleep.

"I've had nights where I've not slept at all, thinking, 'what am I going to do? Who can I speak to?' There's no off switch. You just have to find a way to deal with it.

"In the dressing-room before a game is probably the hardest point. The guys are getting ready to do battle but you're not involved.

"There are going to be problems at some point. I want to get back in the team but I would eventually consider my future if it came to that. There is not a lot I can do about it right now."