RFEF president Angel Maria Villar believes the Real Madrid skipper is superior to first-choice keeper Diego Lopez and played down his side's chances of winning the World Cup
The Spain skipper suffered a hand injury in January, forcing the signing of Diego Lopez, who has since usurped his place in the Blancos line-up.
However, Villar believes that Casillas is still the superior keeper.
"Casillas is the best in the world, but Carlo Ancelotti plays who he wants," he is quoted as saying by AS.
Villar went on to say that Spain are by no means guaranteed winners of the 2014 World Cup, despite their recent success.
"People expect Spain to win, but every team has its limits, and that will happen to us."
Finally, Villar said that Diego Costa will be included in Spain's squad for Brazil, unless he picks up an injury, having switched his allegiance.
"Diego Costa’s situation isn’t new. We should be grateful to the player [for having chosen to play for Spain]. Diego Costa should be fit for the World Cup and if he isn’t he won’t be in the squad."