Various sources including The Daily Mail have confirmed that both Manchester City and Chelsea are on red alert regarding the situation with Real Madrid's Cristiano Ronaldo, the player has become visibly unhappy at the club.

Ronaldo has a buyout clause of nearly €100m and there are only a handful of clubs that would be able to afford the Portuguese national captain. 

At the weekend, Ronaldo failed to celebrate scoring a goal, thus sparking rumours about the players happiness at the club. 

It is thought that Ronaldo is upset with some of the clubs back office officials and feels that he is not receiving the support he deserves. Speaking after the game on his reasons for not celebrating he said 'the people here know why'.

Chelsea owner Roman Abramovich has a history of splashing out over the odds for players that he really wants and can be rather up or down on whether he would move for Ronaldo, but when you are talking about one of the current best players in the world, Abramovich will certainly show an interest.

Whilst Man City manager Roberto Mancini will also welcome the arrival of Ronaldo to his revolutionised squad and the club clearly have the money to do so.

The only other clubs that could compete would be Paris saint-Germain, who could be tempted and Zenit St-Petersburg, who have just signed Hulk and Axel Witsel for a combined fee of €100m. 

Madrid manager Jose Mourinho is not said to be the problem with Ronaldo at all and the two of them still get on very well. With that in mind and the fact that Jose Mourinho has mentioned his desire to return to management in England one day, surely this points to Chelsea or Manchester City running out favourites. We could witness both player and manager moving to the Premier League one day very soon.

The fact of the matter is, when you have your star player unhappy and unsettled, it's surely a downhill slope from there onwards.