Iniesta had a relapse on a thigh injury in the Champions League final while Pique will be out for 10-15 days with a muscle tear, according to the treble winners.
"We listen to everyone: the players, the coaches and the clubs," Del Bosque told a news conference after naming his 23-man squad. "Our medical team is capable of assessing any danger for the player, who is our primary concern.
"We'll take a view on Thursday when the squad joins up. I am confident they will all be ready for the tournament."
Villarreal's Santi Cazorla has just returned from almost two months out with a bone fracture and is also included.
Barcelona's Sergio Busquets comes in as a holding midfielder to replace the injured Marcos Senna, and another youngster, Valencia's Juan Mata, was included to give pace down the flanks.
The European champions, who have won six from six in qualifying for the 2010 World Cup, play their first match against New Zealand on June 14, and go on to face Iraq and then South Africa in Group A.
"These three games concern me," Del Bosque said. "Our job is to make sure the players are fully focused for these games. Afterwards with semi-finals in front us the players would not need motivating."
Squad:
Goalkeepers: Iker Casillas (Real Madrid), Pepe Reina (Liverpool), Diego Lopez (Villarreal).
Defenders: Raul Albiol (Valencia), Alvaro Arbeloa (Liverpool), Joan Capdevila (Villarreal), Carlos Marchena (Valencia), Gerard Pique (Barcelona), Carles Puyol (Barcelona) Sergio Ramos (Real Madrid).
Midfielders: Xabi Alonso (Liverpool), Sergio Busquets (Barcelona), Santi Cazorla (Villarreal), Cesc Fabregas (Arsenal), Xavi (Barcelona), Andres Iniesta (Barcelona), David Silva (Valencia), Juan Mata (Valencia), Albert Riera (Liverpool).
Forwards: David Villa (Valencia), Daniel Guiza (Fenerbahce), Fernando Torres (Liverpool), Fernando Llorente (Athletic Bilbao).
