Cristiano Ronaldo has enjoyed outstanding success with Real Madrid over the last five years. He’s racked up La Liga titles a Champions League trophy and a Ballon d’Or, while scoring 203 goals. But despite all the accolades and accomplishments in Spain, speculation continues to insist that the 29-year-old would consider another go round with former club Manchester United.

Recently Mike Phelan, a former assistant to Sir Alex Ferguson and coach of Ronaldo, told IBTimes UK that the Portuguese superstar is happy at the Bernabeu but a return to Old Trafford might be possible in the future.

"Ronaldo loved his time at Manchester United and if Manchester United were interested in him again then he would listen to that because part of his career has come through Man United,” Phelan said. "But listen, he is where he is because of him being Ronaldo, and at the moment they're successful, Madrid are successful. So I can't see why he would think about coming back to Manchester United now."

Ronaldo rocketed to the international stage during his six-year run with United starting in 2003. He set the league ablaze with 84 goals in 196 appearances, and Madrid acquired him for a then-record £80 million. But his production at Old Trafford was merely a drop in the bucket before Ronaldo would explode in La Liga.

As of now, with Madrid once again atop the Spanish league table and in contention to repeat as Champions League winners, its highly unlikely the squad would consider selling him.

Ronaldo’s agent, Jorge Mendes, even publicly insisted back in October that a move to United was “impossible” and that his client is likely to retire in Spain, according to SkySports.

However, Madrid does have to worry about Ronaldo's happiness, since he could demand a transfer. Earlier this season he publicly questioned the clubs moves that saw Xabi Alonso and Angel Di Maria shipped away, and last season there was speculation of a contract extension dispute as well.

Whether United even wants to pay the expected massive sum to re-acquire Ronaldo is a whole other matter. For one they spent £59.7 million to obtain Di Maria last summer, and spent another £58 million for the rights to Luke Shaw and Ander Herrera before that. United could even make Radamel Falcao’s loan from Monaco permanent.

Still United could find the funds in the huge deal it signed with sports apparel giant adidas back in July. Breaking a 13-year relationship with Nike, United agreed to a £750 million kit deal with adidas that it expects to earn £1.5 billion over the next decade, Daily Mail reported.

Clearly the funds are there, but its ultimately up to Ronaldo to decide.