Brazil and Real Madrid star Ronaldo said he was considering surgery to sort out his knee problem.
Ronaldo has scored 15 goals in World Cup finals
The striker, who has hinted at a move away from Madrid, says he will consult Brazil team doctor Jose Luis Runco.
"We'll talk with Runco and see what's the best way to resolve this problem," said the 29-year-old Ronaldo.
Ronaldo struggled with injuries prior to the tournament, but his three goals saw him pass Gerd Muller as the highest scorer in finals history.
He was criticised for being overweight and ineffective in Brazil's early games, but responded with two goals against Japan and one against Ghana.
Ronaldo was part of Brazil's World Cup-winning sides in 1994 and 2002 and also finished as runner-up in 1998.
The defending champions were the favourites to win the World Cup, but they went out of the tournament at the quarter-final stage to France
Ronaldo said the criticism of the side for failing to go further in Germany was too much.
He added: "I've seen and heard the criticism and it all seems very exaggerated.
Many people were waiting for a brilliant performance from the team and especially from me, something which did not happen
"Our performance was below expectations. We just have to accept it. I think it's too much to look for a culprit for our elimination.
"Brazil won't win every Cup, even though we're the best team in the world.
"Four years ago everyone was happy - the press, fans, politicians - everyone commemorating the fifth World Cup title. Now the losers are just the players and the coaching staff."
Ronaldo defended coach Carlos Alberto Parreira, who led the team to the title in 1994 and was expected to repeat the feat this year.
"The coach can't be the only one guilty for the defeat of the national team," he said.
Ronaldo's team-mate Ronaldinho apologised to the Brazil fans for his below-par performances in Germany.
"Many people were waiting for a brilliant performance from the team and especially from me, something which did not happen," said the Barcelona star on his personal website.
"I regret having left the World Cup without showing our true capabilities.
"There is nothing I can say to change the past. For this reason I want to say 'sorry'."