The goalkeeper suffered a calf injury during Spain's 1-0 defeat to South Africa, having come on as a substitute, and could now miss key games for his club
The 31-year-old replaced Iker Casillas at half-time in Spain's 1-0 defeat to South Africa on Tuesday night but was then carried from the field on 75 minutes after suffering what appeared to be a torn calf muscle.
Valdes - who is set to leave Camp Nou on a free transfer at the end of the current season after opting not to extend his current deal - will undergo a scan in Barcelona on Wednesday.
After the game, the Spanish Football Federation confirmed news of the keepers' impending absence, with doctor Oscar Celada stating: "If the injury is confirmed, he will have to be out for several weeks."
Vicente del Bosque hit out at his Spain side on the back of the defeat in Johannesburg - which came in same city in which they lifted the World Cup back in 2010.
The loss comes after la Roja scraped past Equatorial Guinea with a 2-1 win last week.