Real Madrid midfielder Kaka has undergone an operation on his left knee and could be ruled out for three to four months, the clinic which carried out the surgery said on Thursday.
The Spanish club said earlier on their website that Kaka had suspected meniscus damage and might need surgery.
He was examined by knee and sports injury specialist Marc Martens in Belgium and Martens's assistant at the clinic in Antwerp told Reuters that a half-hour arthroscopic operation was carried out on Thursday morning.
"It went well," the assistant said. "The typical recovery period for this is three to four months."
Brazilian Kaka, who has been plagued by injuries over the past year but recovered to play in the World Cup in South Africa, had left Real's pre-season training camp in California to fly to Belgium.
"He's a very popular player among his team mates and also a very good player but we want him at 100 percent so that he is happy," coach Jose Mourinho told a news conference in San Francisco after Real beat Club America 3-2 in a friendly.
"If we have to lose him for a while it won't be a drama," the Portuguese added. "We have other players and that's that."
Kaka, 28, joined Real from AC Milan in 2009 for a fee of around 65 million euros ($85.3 million). He made 25 league appearances last season, scoring eight goals.
Real play a friendly against Major League Soccer (MLS) club LA Galaxy on Saturday in Los Angeles.
