"I have no specific [physical] problem. There is some overload, but it will not affect my availability," Ronaldo, who turned 28 on Tuesday, told reporters.
"I will analyse what is best for me on Wednesday with the coach and doctors. I am here with body and soul. Whether or not I am at 100 percent, I will play," he said.
Ronaldo, who scored the first own goal of his career during Real Madrid's 1-0 defeat to Granada over the weekend, praised Ecuador and said he believed it will be an "interesting" match-up.
Portugal have failed to win in their last three matches while Ecuador are unbeaten in six games and enjoying a best-ever 12th place in the FIFA rankings, six places above 2014 World Cup hosts Brazil.
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