Casillas could be sidelined for up to three months after successfully undergoing surgery on a broken bone in his left hand.
Doctor Miguel del Cerro, who performed the operation, said in AS: "The operation has gone very well. He will be out for between eight to 12 weeks."
Madrid medical chief Carlos Diez said in a statement on his club's website: "Everything has been phenomenal. Two screws were put in and the hand has been perfect. It has been a complete success from a surgical point of view."