"Honestly speaking, I was hoping that Ronaldo's injury would be more serious," Capello told a news conference on Thursday.
"Of course if he didn't play, then it would be much easier for us to defend."
The Real Madrid forward hurt his left shoulder in Sunday's Spanish league match against arch rivals Barcelona.
A medical examination revealed Ronaldo's injury was not serious and he is expected to start against Russia on Friday.
"Portugal are a top-notch team and tonight, once again, we'll go over the tactical schemes on how to play them," said Italian Capello, who replaced Dick Advocaat following Russia's poor showing at Euro 2012.
"As for Ronaldo, it's always very difficult to stop him," added the former England manager, who also had two coaching spells with Real Madrid.
"Every team tries but it's not so easy. We're going to try to play to the best of our ability in order to neutralise his strengths."
Ronaldo and his Real Madrid team-mate Pepe, who sustained a thigh injury on Sunday, trained on Luzhniki Stadium's artificial turf on Thursday evening and Portugal coach Paulo Bento said he was counting on both to play on Friday.
"They both trained tonight without problems, so it should tell you something," Bento told reporters.
"For me Cristiano is the best player in the world, but with or without him we have come here for victory."
The Russians have made a flying start in their World Cup qualifying campaign under Capello, winning both matches so far, like the Portuguese. On Tuesday, Russia host Azerbaijan while Portugal face Northern Ireland.
