Despite hinting last week that he would use next week's friendly against Uruguay as a chance to experiment, only two uncapped players make the cut, Isco of Malaga and Chelsea’s Cesar Azpilicueta, with Swansea star Michu missing out.
"With this squad, we are left with the bad taste of being able to call up someone who is deserving of a place in the squad. But those who are coming deserve a call-up," Del Bosque told reporters.
"With this being a friendly, it is true that we could have experimented more. But we have to take preparation seriously. We have a very serious opponent who are Copa America holders and were fourth in the World Cup.
“I recognise [Michu's] worth and his goals in the Premier League, but I could not find space this time. It’s the same with [Celta Vigo's] Iago Aspas.
“I am honest and do not hide anything. In the position that he plays, Michu is competing with five or six from our team.
"We have great quality of players in midfield. You only need look at the Under-21 list. Isco and Thiago are great players, but they are not the only ones."