The 63-year-old was expected to trim seven players from his original party on Sunday, but instead named an 18-man squad for the upcoming friendly with Bolivia on Friday.
That selection does not include any Atletico Madrid or Real Madrid players due to their UEFA Champions League final exertions.
Barcelona youngster Gerard Deulofeu, who spent the season on loan at Everton, has been called up and could make his international debut, although there is no room for Jesus Navas, Fernando Llorente or Alvaro Negredo.
Despite their omission from the squad for the friendly in Sevilla, Del Bosque stated it was not the end of the World Cup dream for the trio.
Explaining the thinking behind the decision to delay his announcement, he said: "We've done this because we don't know the physical conditions of all the players and until June 2 we are not obliged to announce it to FIFA.
"We would like for all of them to get here on the 2nd in training conditions. The World Cup kicks off against the Netherlands and we want all of them to be in top form.
"Except for Juanfran and Diego Costa, who we don't yet know how they are after the Champions League final, we know the conditions of the rest.
"Many have chances of getting to the World Cup although they might not feature in this list. Jesus Navas, Negredao and Llorente could make it."
On Deulofeu, he added: "We're confident, he's good on the sides, (on loan at) Everton he's done very well and he's a good solution. If there were any injuries he would be one of the first we'd consider."
Costa limped out of the Champions League final inside the first 10 minutes after struggling with a hamstring injury, with his Atleti team-mates going on to suffer a 4-1 extra-time loss to Real.
Squad in full:
Goalkeepers: David de Gea (Manchester United), Pepe Reina (Napoli)
Defenders: Jordi Alba (Barcelona), Raul Albiol (Napoli), Cesar Azpilicueta (Chelsea), Javi Martinez (Bayern Munich), Alberto Moreno (Sevilla), Gerard Pique (Barcelona)
Midfielders: Sergio Busquets (Barcelona), Santi Cazorla (Arsenal), Gerard Deulofeo (Barcelona), Cesc Fabregas (Barcelona), Xavi Hernandez (Barcelona), Andres Iniesta (Barcelona), Ander Iturraspe (Athletic Bilbao), Juan Mata (Manchester United), Pedro (Barcelona), David Silva (Manchester City)
Forwards: Fernando Torres (Chelsea)
