The doctor who recently performed surgery on Kaka's knee said the Real Madrid forward put his career at risk by playing for Brazil at the World Cup.
Dr. Marc Martens performed the arthroscopic surgery on Kaka's left knee on Thursday after a routine preseason check by Madrid doctors discovered the problem. The Brazil international player will be sidelined three to four months.
Martens said in Friday editions of Spanish newspaper Marca that Kaka played through the pain in South Africa with a nagging injury that soon became "unbearably painful."
Martens said Kaka told him the pain came during the knockout stage matches against Chile and the Netherlands.
Even without one of soccer's biggest stars, Real Madrid brings a formidable lineup to the final match of its two-game tour against the Los Angeles Galaxy at the Rose Bowl.
"All that matters was that the operation was a success," Real Madrid coach Jose Mourinho said. "As the leader of a group, I cannot waste my time crying over a player. I have other players counting on me."
Real will face Major League Soccer's best team in the Galaxy, the league leader in victories (12) and points (40).
Coach Bruce Arena's squad features United States World Cup star Landon Donovan and Edson Buddle, who leads MLS with 12 goals.
All of them traveled to California, where Real Madrid rallied for a 3-2 exhibition victory over Club America of Mexico City on Wednesday night in San Francisco.
Joining that group is the club's biggest offseason acquisition: Sami Khedira, the 23-year-old German midfielder who replaced the injured Michael Ballack at the World Cup.
Khedira — who made only five international appearances before the World Cup — started all seven of Germany's games in South Africa and scored one goal. Real purchased him from VfB Stuttgart in Germany's Bundesliga.
"This is a young group, which is really going to benefit him," said Casillas, Real's captain. "Khedira is brand new and has trouble speaking Spanish. But the squad is doing everything it can to help him adjust."
Khedira did not play against Club America, unlike Real's other new midfielders: Angel DiMaria, Pedro Leon and Sergio Canales, who scored one of the three goals.
DiMaria played in all five of Argentina's games in the World Cup, starting four.
Mourinho — who guided Inter Milan to the Italian league, Italian cup and Champions League titles last season — is using the trip "to try three different tactical systems," he said.
"His training sessions are spectacular," Ronaldo said. "They have great intensity. We don't feel tired because we are extremely motivated."