The Roja legend is concerned by Diego Costa's injury problems and the form of David Villa and Fernando Torres but insists the holders are still among the World Cup favourites
The world and European champions brought in the naturalised Brazilian Diego Costa to provide some extra fire power in attack, but the Atletico Madrid star has been struggling with injury in the build-up to the tournament.
Del Bosque has experimented with using Cesc Fabregas as an unorthodox forward before, and Raul expects Spain to use a similar system once again should David Villa and Fernando Torres be unable to make up for any of Costa's fitness problems.
"David Villa and Fernando Torres were not inspiring for their clubs. We might see Del Bosque switching to 4-6-0 again," said the Real Madrid icon.
"If it helps scoring goals, there will not be any problem. But if it fails, he will not be spared! That's the life of a footballer or a football coach. One bad day and supporters will be after you.
"To defend a World Cup is tougher than winning it. Whether Spain can do it is the question Spanish fans are asking. Vicente del Bosque knows his team and the formations he needs.
"In the absence of [Carles] Puyol, the defence will be weaker. The fitness of Diego Costa will also be a big concern for the manager. Costa was in great rhythm this season before getting injured."
Despite voicing his concerns over Spain's strike force, Raul insists the holders are one of the firm favourites to win the trophy in Brazil - along with the host nation.
"Spain are definitely one of the favourites to win the World Cup in Brazil. There are other contenders but my country ranks first.
"Brazil will play in their back yard and it will boost their confidence. Luiz Felipe Scolari has delivered whenever he has been in charge of a World Cup team.
"Brazil have more attractive defenders than attackers this time."