(CNN) -- The operation on Ronaldo's injured left knee "went well" but the Brazilian striker faces a lengthy rehabilitation as he bids to save his football career.

Ronaldo leaves the field in agony after suffering his latest injury blow against Livorno.

Ronaldo had surgery in Paris on Thursday, the two-hour operation perfomed by Dr. Eric Rolland with Dr. Gerard Saillant, who carried out a similar repair to his right knee in 2000, in attendance.

"The operation went well," said Saillant. "The intervention was of the same type as the one in 2000. The healing period should last nine months," he said in sports paper L'Equipe.

Ronaldo was injured playing for AC Milan in a 1-1 draw with Liverno on Wednesday night and teammate Clarence Seedorf gave CNN a graphic description of the incident.

"It was like a film I already saw," said the Dutch star who was on the pitch when Ronaldo suffered his previous serious injury.

"I saw his reaction, I was frozen by the reality, a bad, bad thing. My heart went out to him because it was his second injury. I hope he has the will to come back," added Seedorf.

Ater the two-hour operation at Pitie-Salpetriere hospital, the three-time FIFA World Player of the Year is likely to need about 10 days of physical therapy, L'Equipe said.

Ronaldo, 31, has battled serious injuries throughout his career, and has played sparingly since joining Milan from Real Madrid in January 2007.

Wednesday's match was only his fifth in 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 team due to a series of recurring problems. E-mail to a friend
Who is recovering in Paris? What team was Ronaldo playing for at the time of his injury? What was Ronaldo's surgery for? Was the operation long? When did his injury occur Where is Ronoldo recovering What was the duration of the surgery? Where did he get injured? What did Ronoldo have surgery on
Ronaldo's AC Milan injured left knee two-hour playing for AC Milan in a 1-1 draw with Liverno on Wednesday night Paris two-hour operation left knee injured left knee
question: Who is recovering in Paris?, answer: Ronaldo's | question: What team was Ronaldo playing for at the time of his injury?, answer: AC Milan | question: What was Ronaldo's surgery for?, answer: injured left knee | question: Was the operation long?, answer: two-hour | question: When did his injury occur, answer: playing for AC Milan in a 1-1 draw with Liverno on Wednesday night | question: Where is Ronoldo recovering, answer: Paris | question: What was the duration of the surgery?, answer: two-hour operation | question: Where did he get injured?, answer: left knee | question: What did Ronoldo have surgery on, answer: injured left knee