Juande Ramos says Real Madrid will struggle to cover the void left by Pepe.
The Portugal defender is out for the season with a knee injury and Ramos insists it could be a "decisive" blow to Real.
The former Real coach said: "For Real Madrid, Pepe is a decisive player. When I was coaching them, in 17 games we conceded five goals. But after Getafe, when he was sent-off, we averaged three goals per game.
"The injury is very important for Real Madrid, they will notice it. Any errors made by his partner, there was always Pepe there to fix it."