Portugal midfielder Joao Moutinho was missing from Portugal training on Saturday, leaving his status for their final World Cup group game against Iran in doubt.
Moutinho sat out Friday's session due to illness and was again absent 24 hours later with the European champions due to face Iran in Saransk on Monday.
The 31-year-old has started both of Portugal's first two matches in Russia, providing the assist for Cristiano Ronaldo in their 1-0 win over Morocco.
Left-back Raphael Guerreiro returned to training with the rest of the squad after sitting out on Friday with a leg complaint.
Portugal are level on four points with Spain in Group B and need a draw from their last game to guarantee a place in the knockout phase.
"We've seen their (Iran's) games and other games at this World Cup. We've understood there are no easy games," said defender Ruben Dias.
"It will be a game in which we should be ready for anything."
"All the teams are ambitious and they know full well it will be a very difficult game for both them and us," he added.
"This is the World Cup. Sometimes you don't start so well but as you play more and more games you believe in yourself and you begin to improve."