Real Madrid left-back Marcelo has suffered a broken foot during training with Brazil and could be out of action until next year.
It was initially thought that Marcelo, 24, had only sustained a twisted ankle after going down during Sunday's closed training session in Poland and it was still hoped he could face Japan in a friendly on Tuesday.
But scans revealed the extent of the damage, with the player breaking the fifth metatarsal in his right foot.
The Brazilian FA has confirmed that Marcelo will be out for up to three months - though Real may yet consider surgery to speed up his recovery.
Marcelo said in a statement on the CBF website: "I will be back soon. There is a long time still left before the 2013 Confederations Cup and I hope to be at it."
It comes at the worst possible time for Real boss Jose Mourinho after his other left-sided defender, Fabio Coentrao, was forced off with a groin injury just 20 minutes into Portugal's World Cup qualifying defeat in Russia on Friday.
Marcelo has started eight of Real's nine games in La Liga and the Champions League this season.