Del Bosque made the surprise decision to include Atletico Madrid midfielder Koke for Wednesday's match in Guayaquil along with Real Madrid new-boy Isco and Real Sociedad defender Inigo Martinez.
Cristian Tello, Fernando Llorente and Alvaro Negredo were also included but there was no place for Manchester United goalkeeper David De Gea, Barcelona midfielder Xavi or Atletico striker David Villa.
Gerard Pique is not included as he is suspended for the World Cup qualifier in Finland, with Martinez taking his place.
"We are early in the season and there are many circumstances we have to consider. It is no longer a friendly," Del Bosque told Marca.
"Beyond the game against Ecuador, it is an international meeting that helps us move closer to September 6, when we play in Finland, and that is our key date in the beginning of this season.
"Pique will not come because he cannot play against Finland and I would prefer to bring someone else."
Del Bosque also explained his decision surrounding Koke.
He said: "Koke has been playing very well at his club. He is a very complete midfielder in his work and does practically everything."
Del Bosque only named five Barcelona players in his squad - goalkeeper Victor Valdes, defender Jordi Alba and midfielders Andres Iniesta, Manchester United target Cesc Fabregas and Tello.
Jose Reina, who recently joined Napoli on loan from Liverpool, is also included along with new team-mate Raul Albiol and Real defender Alvaro Arbeloa.