David Alaba and Isco both tested positive for COVID-19, according to Real Madrid.
The pair are the latest Madrid players to get the illness, bringing the total number of infected players to eight in less than a week.
Last Wednesday, Los Blancos announced that Luka Modric and Marcelo had been placed in quarantine after regular tests revealed they had the sickness.
The following day, Gareth Bale, Marco Asensio, Rodrygo, and Andriy Lunin, as well as Carlo Ancelotti’s son and technical assistant Davide, all tested positive.
All are missing for Madrid’s trip to San Mames on Wednesday to face Athletic Bilbao.
With 43 points from their first 18 games, Ancelotti’s side leads LaLiga by six points, but second-placed Sevilla may cut the distance when they meet Barcelona on Tuesday.