Seleccao boss Carlos Queiroz had named 24 players for his preliminary squad for the competition with fears that Real Madrid defender Pepe would not be fit for South Africa.
Ze Castro had been linked with the drop since the weekend, and the Portuguese Football Federation has now confirmed the reports on its official website.
A statement issued by the federation read, "The national coach, Carlos Queiroz, wants to thank the professionalism, commitment and sense of responsibility that Ze Castro demonstrated in the days he was part of the national squad's training camp."
Portugal, who have been drawn in Group G along with the Ivory Coast, Brazil and North Korea, will kick off their World Cup campaign against the Elephants on June 15th at the Nelson Mandela Bay Stadium in Port Elizabeth.
The Seleccao will play one more pre-World Cup friendly, against Mozambique, on June 8th.
Portugal World Cup squad
| Goalkeepers | - |
| Eduardo | Sporting de Braga |
| Daniel Fernandes |
Iraklis (GRE) |
| Beto | FC Porto |
| Defenders | - |
| Miguel | Valencia (ENG) |
| Ricardo Costa |
Lille (FRA) |
| Paulo Ferreira |
Chelsea (ENG) |
| Ricardo Carvalho |
Chelsea (ENG) |
| Bruno Alves |
FC Porto |
| Rolando | FC Porto |
| Pepe | Real Madrid (ESP) |
| Midfielders | - |
| Fabio Coentrao |
SL Benfica |
| Duda |
Malaga (ESP) |
| Pedro Mendes | Sporting CP |
| Tiago | Juventus (ITA) |
| Deco | Chelsea (ENG) |
| Raul Meireles | FC Porto |
| Miguel Veloso | Sporting CP |
| Simao Sabrosa | Atletico Madrid (ESP) |
| Danny | Zenit St. Petersburg (RUS) |
| Nani |
Manchester United (ENG) |
| Forwards | - |
| Cristiano Ronaldo | Real Madrid (ESP) |
| Liedson |
Sporting CP |
| Hugo Almeida | Werder Bremen (GER) |
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