Cristiano Ronaldo raised fears he would miss the first top-flight Clasico clash of the campaign when he was absent from full training on Wednesday.
Real Madrid confirmed the star forward had "worked separately from the group" amid reports he suffered a calf injury in the Club World Cup final triumph over Gremio.
READ: Easy on the La Liga hype!
Ronaldo scored the winner in that game and his head-to-head showdown with long-standing Barcelona rival Lionel Messi is the anticipated highlight of Saturday's match at the Santiago Bernabeu.
READ: El Clasico: Top 5 encounters between arch-rivals
Madrid is 11 points behind the Camp Nou club, which has not lost in La Liga this season.
Zinedine Zidane's side took the honours when the teams met in the Supercopa, with Ronaldo scoring in the 3-1 first-leg win before being sent off.
WATCH: A historical perspective on El Clasico
He has just four league goals this term, compared to Messi's 14.
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