The speculation surrounding Cristiano Ronaldo’s future at Real Marid shows no signs of abating anytime soon after it was claimed he is dissatisfied with life at the Bernabeu.

Former Real president Ramon Calderon, who signed Ronaldo for £80million from Manchester United in 2009, says the Ballon d’Or winner is considering his options after a frustrating couple of transfer windows and a poor start to the season that has left Real Madrid 17/10 in the Paddy Power football betting odds to win La Liga.

The Portugal superstar was unhappy with the sale of Mesut Ozil to Arsenal last summer, and has now hit out at Real for allowing Angel di Maria and Xabi Alonso to leave during the most recent transfer window.

Ronaldo’s unhappiness has come about despite helping Real achieve ‘La Decima’ last season by winning the Champions League, while he has also collected numerous other individual and team awards during his time in Spain.

So, if Ronaldo really is unhappy and wants to leave, that begs the question regarding where he should go next.

Calderon says a return to Manchester United is on the cards, and given their new tendency to buy ‘galacticos’ it could be a possibility.

Ronaldo still speaks fondly of his time at Old Trafford and would return to much adoration given what he did for the team during his previous spell with United.

Perhaps, though, Ronaldo may fancy a new challenge, and he would not be short of offers from Europe’s super rich if he did snub a return to United.

Chelsea are reportedly ready to offer £60million for Ronaldo, a tempting sum given he is 29, while Paris Saint-Germain want to add him to their growing squad of superstars.

Despite all the interest in him, Real will not want to see their crown jewel leave, for despite the signings of Gareth Bale and James Rodriquez, Ronaldo is still the one they rely on most.

An almighty transfer tussle is brewing in the Spanish capital and, given the nature of football, you should never rule anything out. A return to United looks a distinct possibility but surely Real have the means to keep Ronaldo happy.