Cristiano Ronaldo in a Barcelona shirt, probably forging an unbeatable partnership with his great rival Lionel Messi is the kind of scenario difficult to imagine even on a PlayStation. However, the Real Madrid superstar stoked the "it could happen you know" fire by suggesting anything is possible in football, even a move to Barcelona.

Ronaldo has been constantly linked with a move away from Real Madrid, with those reports only increasing once Rafa Benitez took charge of the club. The Portuguese and the Spaniard reportedly don't get along too well, and there have been stories suggesting the former Manchester United forward could leave the Bernabeu at the end of the season.

PSG or his former team Manchester United have looked like the likeliest candidates, but Ronaldo did not entirely rule out playing for Barcelona or another English Premier League club – be that Manchester City, Chelsea, Arsenal or Liverpool -- despite his Old Trafford allegiances.

"Everything is open, all leagues," Ronaldo told the AP in an interview. "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% certain, I would say so, it wouldn't be a problem. But I have no idea."

When pressed on the possibility of playing for Barcelona or a Premier League club not named Manchester United, Ronaldo was reluctant to categorically rule out a move.

"It's a little more difficult, but ...," he added, with an expression of "anything is possible".

"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% guaranteed. As I said before, there are no certainties in football."

One certainty, though, seems Manchester United's interest in Ronaldo. With the club's spending power increasing with every season, Manchester United should have little problem agreeing a fee and the astronomical wages that the Portuguese will no doubt demand.

However, with PSG also reportedly interested – fuelled further by some of the scenes that followed Real Madrid's Champions League game against the French club – the possibility of Ronaldo moving to Ligue 1 also looks fairly high.

Ronaldo, though, insisted he remains happy at Real Madrid and no decision has been made yet over his future.

"These are always difficult questions to answer because we never know what's going to happen tomorrow," Ronaldo added. "And 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," the 30-year-old Ronaldo said.

"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.

Another destination for Ronaldo could be the MLS, even if the 30-year-old said in a recent interview he does not fancy moving to another continent to finish his career.

"Right now I don't see myself playing in the American league, but that's right now," Ronaldo said. "In two or three years I may think differently."