Bale has featured for Madrid in every league game since recovering from injury to feature in the Clasico defeat to Barcelona in December and started each of their last four matches.
Instead, Benzema will partner Cristiano Ronaldo up front for the Champions League holders, while Lucas Vazquez and Marco Asensio will line up on the wings.
Modric, Casemiro and Isco are also named as substitutes despite starting last week against Eibar, with Mateo Kovacic taking a place in midfield alongside Toni Kroos.
As captain Sergio Ramos is missing from the squad, Nacho Fernandez is drafted in to take his place beside Raphael Varane in defence.
Real Madrid starting XI: Navas, Carvajal, Varane, Nacho, Marcelo, Kroos, Kovacic, Vazquez, Asensio, Ronaldo, Benzema.
Bench: Casilla, Vallejo, Modric, Bale, Casemiro, Theo, Isco