Kaka, who missed Sunday's La Liga game at Malaga with a hamstring problem, said he would spend four days at Brazilian club Sao Paulo for physical reconditioning before Brazil assemble for a pre-World Cup training camp on Friday in Curitiba.
"I'm going to Sao Paulo to be evaluated, they will see my condition and that I won't have any problems," he told reporters.
"I will be 100 percent by the World Cup," added Kaka who was also sidelined for six weeks in March and April.
"It was a very difficult season which I had, but we have examples of players who were not in good form before the World Cup and ended up doing well, so I'm not worried," he said.
(Reporting by Pedro Fonseca in Rio de Janeiro, writing by Brian Homewood in Zurich; Editing by Ken Ferris)