Ronaldo, 32, hasn’t trained all week with the Real Madrid squad having picked up a calf injury against Gremio in the Club World Cup.
He worked away from his team-mates today and his absence would be a huge blow as Real bid to close the game on Barcelona.
However, Sky Sports pundit Balague says the feeling at Real is that Ronaldo will pull through to play on Saturday.
Balague said: “He got a knock against Gremio only five or six days ago but he did train today on his own.
“It seems like he’s going to be okay. You won’t be surprised to hear that niggling injuries players have clear before El Clasico.
“He should be okay, they all expect.
“It will be interesting to see the choice not so much between Ronaldo and Benzema, who will play, but who will be next to them.
“Will it be Isco or Bale? If Gareth Bale feels 100 per cent he may actually be the surprise name in the line-up. Otherwise, it will be Isco among the usual suspects.
“Real are 11 points behind Barcelona and as Sergio Ramos has said, unless we win El Clasico, we are out of contention.”
Real sit fourth in La Liga and they are 11 points behind Barcelona, although they do have a game in hand.