Ronaldo has failed to build on his status as one of the world's best players because of a lack of professionalism.

This is according to his former coach and current England boss Fabio Capello. Ronaldo, 32, has now recovered from a serious knee injury and signed for Corinthians in his homeland after 14 years playing in Europe.

However, his career has drifted in recent years, most notably at Real Madrid before and during Capello's time at the Bernabeu.

"Ronaldo remains the strongest player I have ever coached," Capello told Sky.it.

"However, he is also one of the players that has taken less care of himself physically because had he done that, with the quality he had, he would have been unsurpassable for years and years.

"Instead, he didn't take care of himself and I believe that certain injuries were due to the fact that he was not a perfect professional in terms of training, diet and everything else."

Capello coached Ronaldo at Real Madrid during the 2006-07 campaign.

The former Inter Milan and Barcelona star is a two-time Ballon D'or winner, and won the FIFA Player of the Year award three times.