PARIS -- AC Milan striker Ronaldo is unsure whether he'll be able to play after needing surgery to repair a ruptured tendon in his left knee.
"Physically it will be difficult and mentally it will be very difficult," said Ronaldo, who was released from the Pitie-Salpetriere hospital on Friday after undergoing surgery a week ago.
Hospital officials said the operation went well, but the three-time FIFA player of the year said it was too early to tell if he would return to the field. Ronaldo is not expected to play again for at least eight or nine months.
"I have not decided what should be done," said the 31-year-old Brazilian striker. "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."
Ronaldo was injured in AC Milan's 1-1 draw with Livorno in the Serie A last week.
The top-scorer in World Cup history with 15 goals for Brazil, Ronaldo had a 2-hour operation at the end of last week and followed that with eight days of physical therapy.
"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."
He 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 his finishing skills.
Ronaldo scored twice in a 5-2 win over Naples on Jan. 13, where his play with 18-year-old Brazilian Alexandre Pato had Milan fans dreaming of things to come.
He lost his place in the Brazil team after the 2006 World Cup, but managed three goals during the competition to increase his international total to 61 in 97 games.
Ronaldo has sustained serious injuries throughout his career, and eight years ago had a career threatening right-knee injury when playing for Inter Milan. He missed the following season, but came back strong at the 2002 World Cup, guiding Brazil to its fifth title with eight goals, including two in the final against Germany.
The match against Naples was only his fifth in the Serie A this season after injuring his thigh during preseason training on July 31. He returned in November, but has been in and out of the lineup because of 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 teammates, 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."