Ronaldo, 27, had hurt his left shoulder while attempting an over-head kick in the 2-2 draw against Barcelona at the weekend. Portugal will face Russia in Moscow on Friday and Northern Ireland in Porto on Tuesday.
Ronaldo returned to training with fellow Real teammate and defender Pepe who also suffered a knock during the 2-2 'Clasico' draw with the Catalans.
Meanwhile, Portugal coach Paulo Bento was hoping that Ronaldo remains 100 per cent fit and contributes to the team.
"We will have to see if there is any reaction and assess how he is," said Bento. "But of course it would make a big difference to us, if he can play. He is the best there is, and he will certainly get my vote for world player-of-the-year."
However, Russia coach Fabio Capello wished that Ronaldo's injury was more serious so that his side would not have to defend against him.
"Honestly speaking, I was hoping that Ronaldo's injury would be more serious," Capello said.
"Of course if he didn't play, then it would be much easier for us to defend," the former England manager said.
Ronaldo is in sublime form this season and the Italian coach will try his best to stop the Portuguese.
"As for Ronaldo, it's always very difficult to stop him. Every team tries but it's not so easy," Capello said.
"We're going to try to play to the best of our ability in order to neutralise his strengths," he said.