The 61-year-old was criticised for leaving Juan Mata and Fernando Llorente out of the squad for the World Cup qualifiers with Belarus and France but believes that the choices he has at his disposal make it impossible to not upset some of his players.
Del Bosque told Radio MARCA: "We have 23 players which I think are a lot for two matches, but we have to cover any possible eventuality.
"We aren't here to please people, but to field the best team.
"It's due to competition for places. [Mata] plays in an area where we have a lot of players."
The world and European champions travel to Minsk to face Belarus on Friday.