Valdes tore the anterior cruciate ligament in his right knee during Barcelona's 3-0 win over Celta Vigo on Wednesday and is expected to be out for six months.
He seems sure to miss out on the 2014 FIFA World Cup in Brazil but instead of talking about a potential replacement, Del Bosque was more worried about the player.
The 63-year-old told Spanish radio station Onda Cero: "It's very sad. It's a very bad injury for him.
"It's always bad when you can't play for your club or at the World Cup.
"I don't want to get into who might be Victor's substitute (though). The first thing is to hope he recovers well. At the moment we've not thought about anything else.
"He is our only thought as he is in a bad situation."
Valdes' Barcelona career appears to be over, with the 32-year-old set to leave the Catalan giants at the end of this season.
Del Bosque has no shortage of goalkeepers to choose from in Valdes' absence though, with Iker Casillas and Pepe Reina set to fight it out to be his new first choice.
