The world and European champions, who top the group by one point from France after five of eight matches, will be missing midfielders Sergio Busquets and Xabi Alonso for the game in Helsinki before they play a friendly against Chile in Geneva on September 10.
Del Bosque told Tuesday’s edition of As sports daily there was no need to make a drama out of the absences, saying Spain had plenty of other players capable of rising to the occasion.
“We have a number of important midfielders missing,” the former Real Madrid coach said before the squad met up at the Spanish soccer federation (RFEF) headquarters outside Madrid on Tuesday.
“But those that are here will do a good job because they are in excellent shape.
“We are relaxed about the trip to Finland due to the players we ultimately have selected.”
Del Bosque mounted another strong defence of his captain and goalkeeper Iker Casillas, who has yet to win back his place in the Real Madrid starting line-up after injuring his hand and then falling out with coach Jose Mourinho last season.
Barcelona keeper Victor Valdes has been in fine early-season form, prompting speculation that he might start Friday’s match.
“I am not saying, nor will I say, that Iker Casillas has to play for Madrid,” Del Bosque told As.
“What I am doing, and what I will do, is defend him because he, Casillas, is the captain of the national team and a lad who is part of Spanish football, and a key part,” he added.
“He is going through a bad patch and he needs the support of those who appreciate him and hold him in high regard.
“It’s not a comfortable situation for anyone but above all it’s uncomfortable for him.”
Spain can take a big step towards securing their place in the tournament in Brazil next year with a win in Helsinki.
However, they will not take their opponents lightly after surrendering the lead to draw 1-1 with them in Gijon in March. Finland are third in the group, four points behind the French.
“France are lying in wait and Finland still have a chance and will be looking to beat Spain and fight for a playoff spot,” Del Bosque said.
“We have to be very careful about this match. What’s more, I recall that all Finland’s qualifiers have been close, meaning they are tough opponents who improve at their own stadium.
“We drew in Gijon in March and the last time we visited Helsinki in 2007 we could not do better than a 0-0 draw.
“I don’t expect an easy game but we are confident that we will get the result we want and then wait for the matches against Georgia and Belarus in October.”
(Reporting by Iain Rogers, editing by Clare Fallon)