Expectations were high that the Real Madrid striker would return to la Furia Roja after two-and-a-half years following his good form at club level, but it was not enough.
Instead, Del Bosque has revealed that he has never been sure about recalling Raul and feels that Guiza has impressed him enough in previous Spain games to warrant the call.
"I have always had my doubts about [Raul]. I am not a radical. Negrdo and Joseba Llorente also had a chance," AS quote him as saying.
"It is the same with other positions too, like the goalkeepers. I valued the way both Palop and Valdes are playing, but I was inclined to choose Diego Lopez.
"It was important to bring in a third goalkeeper to cover because of such a long time together."
Guiza may not have been playing regularly for Fenerbahce, but Del Bosque knows what he can bring to the team and feels that the player deserves his chance.
"With Guiza one must value the human side too, as well as the fact that we are talking about a super professional," he continued.
"He had an injury and has not been starting for his team, but he is having a few minutes and is vying for a place with Turkey international Semih Senturk.
"He is important for us and he helps us a lot. In the last game against Belgium he set both goals up for David Villa."
Carles Puyol has also been left out, and replaced by club-mate Gerard Pique, and Del Bosque revealed why he had been forced to omit the Barça skipper.
"We spoke with his coach and with him and the player said he would not play this Sunday and would be doubtful for the next one because he is not fit," he added.
"Because of that, I preferred not to call him up."
Lucas Brown, Goal.com