Xabi Alonso has said Real Madrid have suffered "incredible" bad luck with injuries sustained during the latest round of international matches.
But he told reporters he was sure coach Jose Mourinho would come up with a solution for the forthcoming games against Celta Vigo in La Liga and Borussia Dortmund in the Champions League.
Most of Madrid's internationals returned to training at the club's Valdebebas facility on Wednesday, but their three injured full-backs - Alvaro Arbeloa, Marcelo and Fabio Coentrao - were all absent.
Karim Benzema, Sami Khedira and Raphael Varane also did not take part in the recuperation session, Real's official website said, while Argentine internationals Angel di Maria and Gonzalo Higuain were due to return on Thursday.
Alonso, speaking while making a commercial appearance before training on Wednesday, said: "It is incredible that, in just seven days, the three [full-backs] have gone. But I am sure the boss is already working on a solution in his head."
Mourinho could decide to play Sergio Ramos out of position at left-back when Celta visit on Saturday, or alternatively promote one of Madrid Castilla defenders Nacho, 22, or Jorge Casado, 23, for a rare first-team appearance.
Alonso said he was sure the Portuguese coach would make the right decision, adding: "It is not my job to decide who plays full-back. The boss will be thinking of solutions.
"I concentrate on playing, and I will try and support whoever plays there, whether it is someone from the youth system or another team-mate."
Benzema, who limped off late in France's 1-1 draw with Spain on Tuesday, and Higuain, substituted in Argentina's 2-1 win in Chile with an ankle knock, remain doubts for this weekend's game, but Alonso said he hoped both would be available.
"We hope there is not the same bad luck with forwards," he said. "We hope that both Pipa and Benzema are ready for Saturday."
The Basque midfielder suggested the heavy demands of international and club football were to blame for so many players picking up injuries.
"The calendar is very cramped," he explained. "When you play at the top level, you end up playing 60 or 70 games a season. There should a new setup to improve the distribution of the games. It would be good for everyone - fans, players and clubs."