The 30-year-old has come in for some criticism for his performances thus far, with the striker scoring just once in Brazil's four fixtures.
Last year, Fred hit five goals in helping his nation to Confederations Cup success - including a brace against Spain in the final - and Kaka claims that the Fluminense man will soon come good.
"We should remember that Fred had a very good Confederations Cup last year," the 32-year-old said in an interview with the Times of India.
"He has a lot to give to the team. He's had a slow start but picked up and can become one of Brazil's big players as the tournament goes on."