Real Madrid forward Cristiano Ronaldo has not ruled out the possibility of a sensational move to the club's arch-rivals Barcelona, but admits the chances of it happening are "almost impossible".
The Portugal international says "everything is open" as he continues to be questioned about where he could end up in the future.
Ronaldo has been linked with Paris Saint-Germain in recent weeks, but laughed it off on Tuesday as nothing more than speculation.
However, when asked about a switch to Camp Nou or back to Old Trafford to rejoin Manchester United, Ronaldo refused to rule anything out.
"It's a little more difficult," he told the Associated Press.
"There are things that you kind of already have an idea, that to play one day for Barcelona would be almost impossible, or to play for another English club other than Manchester, it's very complicated.
"But that's not 100 per cent guaranteed. As I said before, there are no certainties in football. Everything is open, all leagues.
"I may end my career here with Real Madrid. I'm just being honest. I don't know what's going to happen tomorrow. If I was 75 per cent certain, I would say so, it wouldn't be a problem. But I have no idea."
Ronaldo's current contract at Madrid runs until the end of the 2017-18 season and the 30-year-old hinted he could be interested in a move to MLS.
"Right now I don't see myself playing in the American league, but that's right now," he said. "In two or three years I may think differently.
"As a football professional, this is always an unknown, so I prefer to stay in the present.
"The present is good and I'm enjoying being at Real Madrid. But in a few years I don't know how I'm going to be thinking.
"When it's closer to ending my contract I'm going to have to make decisions, whether it's staying at Real Madrid or going to another club or ending my career in a few years.
"It's normal. That's why I'm not worried, because I know that everything has a beginning and everything has an end.
"I'm ready for that. I'm ready to stay at Real Madrid, to leave, to end my career when it's time. It's part of my job."
