Moutinho on Friday missed his team's training session held at Kratovo training camp near the Russian capital.
The Monaco midfielder caught a flu but he is reportedly is fit for the match against Iran.
Moutinho was one of Portugal's best players in their 1-0 win over Morocco and provided the assist with the set piece which saw Cristiano Ronaldo score the only goal of the game in the fourth minute.
However, he was unable to train on Saturday due to illness after also being forced to sit out Friday's session for the same reason as Portugal prepare for its game against Iran.