Modric replaces Marko Rog in midfield as coach Ante Cacic makes five changes including bringing in Domagoj Vida and Ivan Strinic for defenders Tin Jedvaj and Sime Vrsaljko.
Ivan Peritic is set to switch to the left wing in place of Marko Pjaca to make way for Marcelo Brozovic on the right, while forward Mandzukic replaces Nikola Kalinic up front.
Portugal have made four changes with three coming in defence where Jose Fonte takes over from Ricardo Carvalho while full backs Cedric and Raphael Guerreiro replace Vierinha and Eliseu.
In midfield, coach Fernando Santos has opted for Adrian Silva instead of Joao Moutinho, leaving the attacking pairing of Cristaino Ronaldo and Nani intact up front.
(Reporting by Philip O'Connor; Editing by Ken Ferris)
