Casillas, the Real and Spain captain and a fixture in both teams for more than a decade, sustained the injury during a King's Cup game in January when team-mate Alvaro Arbeloa kicked his hand while trying to clear the ball.
Real coach Jose Mourinho brought in Diego Lopez from Sevilla as cover and although the break has healed the Portuguese has left Casillas out of the team, fuelling speculation about a rift between the pair.
Del Bosque said at an awards ceremony in Barcelona on Wednesday he expected to include Casillas in his squad for the Confederations Cup in Brazil in June, the warm-up event for the 2014 World Cup where Spain, who are also the European champions, will defend the title they won in South Africa in 2010.
"We know that he is a legend of Spanish football, that nobody has achieved what he has, and then in 10 days he is put in an uncomfortable situation," Del Bosque said.
"I don't imagine that in England they would question [Peter] Shilton in this same situation or other players that have been legends in their national teams," added the former Real coach.
"We therefore are obliged to protect players that have given so much to the national side."
Lopez, a former Spain international who came through Real's youth ranks and had a five-year stint at Villarreal, has been in fine form since returning to his boyhood club.
Casillas has sometimes been criticised for a weakness against high balls and Lopez, who is almost two metres tall, is seen as more effective dealing with crosses.
While he may not possess the same lightning reactions or athleticism as Casillas, he is a fine shot stopper and a solid ball player.
"The important thing is that he [Casillas] is recovering, he is training and we have time to take any decisions," Del Bosque said.
"I must say that he is our player, one of the best that has represented us in more than 140 games and we have a lot of affection for him. It is normal that he would be with us [at the Confederations Cup]."
Casillas, who will be 32 next month, has made 143 appearances for Spain, more than any other player.
Under his captaincy they became the first nation to win back-to-back European Championships with a World Cup in between.
Real play their Champions League semi-final first leg at Borussia Dortmund next Wednesday, with the return leg in Madrid the following Tuesday.
