Real Madrid duo Roberto Carlos and Fabio Cannavaro have been ruled out of their side's El Clasico clash against Barcelona on Saturday due to injury, the Spanish giants said on Friday. Italian international defender Cannavaro will be out of action for between 10 and 12 days after straining his right groin muscle in the warm-up before Real's UEFA Champions League encounter against Bayern Munich. Carlos's injury is more serious as he could be sidelined for up to month after suffering a slight muscle tear in his right leg during the same European match. Los Meringues will also have to do without David Beckham and Jose Antonio Reyes after both players suffered knee ligament injuries in Real's Primera Liga game against Getafe last weekend.