The transfer window may have closed, but speculation has yet to rest linking the winner of the last two Ballon d’Ors with a blockbuster move away from Real Madrid. Cristiano Ronaldo’s future was the subject of numerous rumors for much of the summer, amid talk of his unhappiness at the Bernabeu and strong interest from Paris Saint-Germain. While he predictably remained with the Spanish giants, there are already signs that what happened in the past few months was just a forerunner for a major battle over his signature at the end of this season.

According to The Sunday Times, PSG are ready to pay a world record €150 million fee to land the Portugal forward as well as a base salary of around €20 million after tax. The report also claims that PSG had a €120 million offer rejected for Ronaldo in the last transfer window. Meanwhile, the Daily Star is among the publications reporting once again that, were Ronaldo to be available, his former club Manchester United will be heavily involved in the bidding process.

Certainly, next summer is set to be key in deciding whether Ronaldo goes onto see out the rest of his prime years at Real Madrid, or seeks a fresh challenge at another of Europe’s giant clubs. It will be then that the 30-year-old enters the final two years of a contract he signed two years ago. That last deal was agreed when Ronaldo also had two years reaming on his contract and after he flirted with a move back to Old Trafford, from where he left for Real Madrid for a then-record €94 million fee.

Real Madrid will not be keen to have such a valuable asset run down his contract, increasing the possibility that he could leave for nothing in two years. Yet there is no certainty that the 10-time European champions will be prepared to offer Ronaldo the same incredible financial offer that both PSG and Manchester United would likely be willing to present in order to lure one of the world’s most famous athletes to their club.

And it’s possible that Ronaldo may desire a change of scenery. Playing for Real Madrid was his dream, but by the time next summer rolls around he will have achieved almost everything available at the Bernabeu. As well as becoming, Spanish, European and world champion, he is now just three goals away from overtaking Raul to become the leading scorer in the history of the club.

At that point, the challenge of delivering PSG a first ever European Cup may appeal. He would be the undoubted star of the show in Paris and in France, although the comparatively low standard in Ligue 1 may be a drawback for a competitor as fierce as Ronaldo.

Then there is the prospect of returning to the venue where he became a global star. His mentor Sir Alex Ferguson is now long gone and it has been lean times for Manchester United since then. But he could be tempted by bringing one of the world’s biggest clubs back to the summit in Europe to follow up the Champions League title he inspired them to in 2008.

Or could he go elsewhere? Manchester City could afford him, although Ronaldo has previously suggested that his affection for the other Manchester club would make that move difficult. Chelsea, too, have in the past been credited with an interest, however the relationship between manager Jose Mourinho and Ronaldo broke down at Real Madrid.

Whatever happens, there is unlikely to be a shortage of suitors for a player who continues to score goals at a rate matched only by Lionel Messi.