Last I saw Carvajal on the list of injured players and he had undergone surgery so that conditions like this could continue to be a problem. Although there are a number of substitute players in that position, it may be different from the abilities possessed by Carvajal.
Only Lucas Vázquez as the left defender recently for Real Madrid after Dani Carvajal got injury and out until the end of this season, its big problem because Madrid less option for left defender position than central defender because have other player can play well on that position. No doubt with Carlo Ancelotti tactician how make rotation and moving some players put them on new position, but have an exceptional because Ancelotti never make huge rotation on left defender although with possibility for playing Eder Militao on Dani Carvajal's position.
I think two months left before January window transfer opening, Madrid need new approach for signing new players on left defender position because have many important match on second half make most busy schedule matches with Madrid will play on FIFA Club World Cup indeed have target keep defending the La Liga and UEFA Champion League trophy in this season.