The 33-year-old midfielder, part of his country's triumphant group 11 years ago, last represented Brazil in a friendly against Chile in April, but has been impressing in his homeland with Atletico Mineiro.
Ahead of his anticipated return from a thigh injury at this month's Club World Cup in Morocco, Ronaldinho told FIFA's official website he had not given up hope of being selected again by national coach Luiz Felipe Scolari.
"He is a very direct person and is always open with me. I know that there are still opportunities available for those who are playing well," said Ronaldinho.
"He seems to have the core of his squad decided, but whoever is in good form at the right time will go too.
"I'm always working hard to improve. If there is a chance of playing in the World Cup, I'll be ready, and I'll be at my peak. My goal is to always be at my best."
"It was great to be back with the national squad (earlier this year). Luiz Felipe Scolari and I have won so much together and we have a good relationship."
