The coach says that he retains the utmost respect for the players who helped La Roja win three major titles but warns that he needs to make space for those "coming through"
On Friday, the 63-year-old announced his party for Wednesday's friendly against Italy, with Fernando Torres, David Villa, Juan Mata and Fernando Llorente all notable absentees.
Del Bosque, who led Spain to the European Championship in 2012 as well as World Cup 2010, declared that loyalty will not come into the equation when he sits down to select his squad for Brazil.
"The extraordinary generation of players that helped us become champions have a place in my heart," the former Real Madrid boss told Cadena Ser, "but I also have to keep in mind that I need to be flexible and give those who can bring something to the team a chance.
"I would be a poor national team coach if I didn't act in that way.
"I have a huge amount of affection for those who made us world champions but, at the same time, we have to look at those who are coming through."
Spain open their World Cup campaign with a Group B match against Netherlands - whom they defeated 1-0 in the 2010 final - in Salvador on June 13.
La Roja will then go on to face Chile in Rio de Janeiro on June 18 and Australia in Curitiba five days later.