The 32-year-old has not featured for the national team since March 2013 and, although he has impressed since returning to Milan from Real Madrid earlier this season, Luiz Felipe Scolari has never recalled him.
Kaka was not the only big name to be missing from Brazil's provisional squad for their home tournament, with the likes of Robinho, Philippe Coutinho and Lucas Moura also left out.
Brazil's coach has remained consistent in his selections heading to the World Cup and Kaka admits it would have been a surprise had he been picked by the 65-year-old.
"It's a pity, but I am not sad because I did everything I could," he is quoted as telling Sky Sport Italia. "Scolari has always been consistent and made his choices.
"He hadn't called me recently, so it would've been a surprise to be included.
"Robinho took the decision the same way I did, we gave it our all to go to the World Cup, but Scolari made other choices."
Kaka has scored seven goals in 28 league appearances for Milan in what has been a disappointing campaign for the 18-time Serie A winners.
