The Wolverhampton Wanderers midfielder has enjoyed a stellar campaign in the Championship and has featured in his nation's most recent internationals.
However, the 21-year-old is one of 12 players to miss out on the final squad as Portugal look to back up their victory at Euro 2016 two years ago.
Portugal face fixtures against Spain, Morocco and Iran during the group stages in Russia.
Goalkeepers: Anthony Lopes (Lyon), Beto (Goztepe), Rui Patricio (Sporting)
Defenders: Bruno Alves (Rangers), Cedric Soares (Southampton), Jose Fonte (Dalian Yifang), Mario Rui (Napoli), Pepe (Besiktas), Raphael Guerreiro (Borussia Dortmund), Ricardo Pereira (Porto), Ruben Dias (Benfica)
Midfielders: Adrien Silva (Leicester), Bruno Fernandes (Sporting), Joao Mario (Inter Milan), Joao Moutinho (Monaco), Manuel Fernandes (Lokomotiv Moscow), William Carvalho (Sporting)
Forwards: Andre Silva (Milan), Bernardo Silva (Manchester City), Cristiano Ronaldo (Real Madrid), Gelson Martins (Sporting), Goncalo Guedes (Valencia), Ricardo Quaresma (Besiktas)