The burly Llorente has an impressive seven goals in 12 appearances for the world and European champions and netted a double against Lithuania and the winner against Scotland in Euro 2012 qualifying last month.
Torres, who had a poor World Cup on his return from knee surgery, suffered an ankle ligament strain in Saturday's 2-0 Premier League defeat at Stoke City but would join up with the Spain squad in Madrid, Liverpool said on Sunday.
The match in Lisbon is also an opportunity for Portugal to avenge their World Cup last-16 defeat to the Spanish at the end of June, when striker David Villa scored the only goal in the 63rd minute.
Spain coach Vicente del Bosque was widely praised for his decision to replace a weary-looking Torres with Llorente around a quarter of an hour into the second half in Cape Town.
His disruptive presence upset Portugal's concentration and he was involved in the move that led to Villa's winning goal.
Portugal coach Paulo Bento has Jose Boswinga available again following the Chelsea right-back's recent return from a knee injury sustained in October 2009.
Appointed in September to replace the sacked Carlos Queiroz, Bento led his side to morale-boosting Euro 2012 qualifying wins over Denmark and Iceland last month that revived their stuttering campaign.
Teams (possible):
Portugal: 1-Eduardo; 4-Joao Pereira, 3-Pepe, 6-Ricardo Carvalho, 5-Fabio Coentrao; 16-Raul Meireles, 8-Joao Moutinho, 20-Carlos Martins; 17-Nani, 18-Hugo Almeida, 7-Cristiano Ronaldo.
Spain: 1-Iker Casillas; 15-Sergio Ramos, 3-Gerard Pique, 5-Carles Puyol, 11-Joan Capdevila; 8-Xavi, 16-Sergio Busquets, 6-Andres Iniesta, 20-Santi Cazorla; 7-David Villa, 19-Fernando Llorente.
