Crocked Ronaldo yet to decide on playing future as he faces long way back

"Physically it will be difficult and mentally it will be very difficult," Ronaldo said, as he left the Pitie-Salpetriere hospital in Paris after surgery a week ago.

The hospital has said the operation went well but that it was too early to say whether the 31-year-old Ronaldo would return to the field.

"I have not decided what should be done," Ronaldo said. "My will is to keep on playing. My heart tells me this, but my body is showing me signs that it's tired, that it is asking for rest."

The three-time FIFA world player of the year was injured in Milan's 1-1 draw with Livorno in the Serie A last week.

Ronaldo, the top-scorer in World Cup history with 15 goals for Brazil, had a successful two-hour operation at the end of last week and followed that with eight days of physical therapy.

More treatment will follow in a specialized centre, but Ronaldo will not be able to play again for at least eight or nine months.

"If, at the end, I am back in shape physically and I can play, so much the better," Ronaldo said. "Otherwise, it will be a difficult decision to take, but that will be the decision."

The 31-year-old striker has played only sporadically since joining Milan a little more than a year ago, but his scoring rate of nine Serie A goals in 16 starts showed that - when fit - he had lost none of razor-sharp finishing.

He scored twice in a 5-2 win over Naples on Jan. 13, where his instinctive understanding with 18-year-old Brazilian Alexandre Pato had Milan fans dreaming of things to come.

Ronaldo lost his place in the Brazil team after the 2006 World Cup, but still managed three goals during the competition to take his international total to 61 in 97 games.

Milan coach Carlo Ancelotti previously told Italy's Gazzetta dello Sport newspaper that he was "convinced" Ronaldo will return to play "because soccer is his world and we are waiting for him."

Ronaldo has battled serious injuries throughout his career, and already had a career threatening right-knee injury when playing for Inter Milan eight years ago. He missed the following season, but came back strongly at the 2002 World Cup, guiding Brazil to its fifth title with eight goals, including both in the final against Germany.

The match against Naples was only his fifth in the Serie A this season after injuring his thigh during pre-season training on July 31. He returned in November, but has been in and out of the team due to a series of recurring problems.

"I must first win the battle with my body," Ronaldo said. "I regret it has happened this way with AC Milan. I want to thank all my team-mates, all the people who supported me."

Eric Rolland, the doctor who operated on the knee, said Ronaldo faces a long road back.

"The end result is 50 percent the operation, and 50 percent the therapy that will follow," Rolland said. "Anything can happen in the next three months, as surgery is not an exact science."

Ronaldo's contract expires on June 30, putting Milan in a tough position.

"It is not now that I can think about my contract," Ronaldo said. "I am not asking myself whether I can continue to play with Milan or with other teams in Europe. My mind is not on that. But my dream is to finish my career with (Brazil's) Flamengo."