AS.com

Reports of Cristiano's possible departure from Real Madrid at the end of the season has alerted the top clubs in Europe

Three clubs have emerged as possible front runners to sign the Portuguese if he does indeed leave the Santiago Bernabéu: Manchester United, Manchester City and Paris Saint-Germain.

United have the advantage that Cristiano has admitted publicly that he longs to work with Alex Ferguson again and has fond memories of his time at Manchester Untied. The Red Devils have the least resources out of the three clubs and are the least likely to be able to afford his transfer fee, but as the player has a lucrative deal with Nike, the same company that manufacturers Manchester United's kit, it is possible that the company could contribute to his transfer fee.

The second club in line to sign Cristiano are United's eternal rival, Manchester City, who expressed their interest in signing him in the last two summers. It has been reported that ownerSheikh Mansour ben Zayed Al-Nahyane would be ready to offer around 200 million euros to land the Portuguese should he become available, while the club's continued interest in hiring Pep Guardiola as their next coach could see the Catalan become Ronaldo's coach.

Paris Saint Germain are the final club that could sign Cristiano. Owner Sheikh Tamim bin Hamad Al Thani has spent 257 million euros on players since taking over the Paris club in 2011, signing Zlatan Ibrahimovic, Thiago Silva and Javier Pastore, but bringing Cristiano to the Parc de Princes would be the biggest coup of them all.