Vicente del Bosque opted to omit the Mestalla frontman in favour of the likes of Fernando Torres, Alvaro Negredo and Fernando Llorente, despite netting 27 goals in all competitions for Los Che.
Now, Basque hitman Aduriz claims Soldado was unlucky to miss out and deserved to be part of the world champions' squad that will travel to Poland and Ukraine.
"The truth is that he has had a fantastic year and for me merits to be included, but it is the coach who makes the decisions and must be respected,” the 31-year-old told Marca.
“However my personal opinion is that he has done enough to get in the squad. I have communicated with him through messages and tried to encourage him.”
The Los Che striker then pointed out that Spain are favourites for the European Championship in his eyes, but knows it is all to play for.
"I think Spain are the favourites; they won the last World Cup and although I think there are some very good teams, they are the favourites, but we'll see what happens," he concluded.
Spain open their Euro 2012 campaign against Italy on June 10.