It is clear that Ancelotti will find a player on the bench who can replace the injured one, but does Real have a player of Carvajal's level on their bench? This is a rhetorical question, there is no such player, but they will just have to learn to play without him because he is out due to injury for a whole year. El Clasico is always a special game, and this confrontation is always unpredictable, every season due to different circumstances one of the teams can be stronger and despite Real's losses, I am ready to say that Barcelona can beat Real.
I am very confident that Carlo Ancelotti will be able to find a solution, perhaps even changing strategy and formations
After all, you may have noticde how he is a strategist on the football pitch and Real Madrid have in fact won a lot with him while spending relatively little, just see past years