The attacker picked up a strain in the adductor muscle of his left thigh during Portugal's 6-2 win over Bosnia & Herzegovina on Tuesday in the second leg of the Euro 2012 play-off.
Ronaldo and his team-mate Alvaro Arbeloa both sat out Madrid's training session on Wednesday, but the Portuguese has now played down his chances of missing the game.
"I'm fine," Ronaldo admitted at the launch of his new Nike boots, "I think I'll play against Valencia".
Madrid head into the clash at Mestalla as La Liga leaders with 28 points from 11 matches, while Valencia are third on 24 points. The clash kicks off at 22.00CET.
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