Real coach Zinedine Zidane hauled off Ronaldo with 20 minutes to run.
Deportes Cuatro cameras caught Isco and James discussing the change, with the former visibly stunned by the decision.
Zidane said after the 2-2 draw that there was nothing unusual in the change.
"We've got a game on Tuesday and I thought that it was the right time to bring him off. That's all there is to it. He always wants to play and be out there on the pitch, but I've also got to think about the player and he needed to rest and think about Tuesday."