Defending champions Spain face Bolivia on Friday (May 30th) night in their penultimate warm-up match ahead of the World Cup.
Spain have been drawn in Group B - the 'group of death' - along with Australia, Chile and the Netherlands.
Del Bosque revealed that striker Diego Costa will undergo some 'medical procedures', but added that it looked 'good' for the Atletico Madrid striker as he hopes to participate in Brazil.
Costa was forced off in the Champions League final defeat to city rivals Real Madrid with a muscle tear in his right leg.
The Spanish head coach praised his players for their efforts, adding that the squad looks promising in their training sessions.
Goalkeeper Pepe Reina also spoke to the media on Thursday, saying uncertainty over his club future will not affect his focus heading into the World Cup.
Spain will travel to the United States following their friendly with Bolivia, where they will face El Salvador before making the journey to Brazil.
They begin their World Cup defence facing the Netherlands in Salvador on June 13th - a repeat of the 2010 final.