Barcelona full-back Douglas is set to miss up to two months of action after fracturing a bone in his right foot during the 0-0 draw with Villanovense on Wednesday.
The Spanish champions were held in the first leg of their Copa del Rey opener at the Estadio Romero Cuerda with Douglas playing the full 90 minutes.
However, the Brazilian has since been found to have fractured the scaphoid bone in his foot and looks set to miss much of November and December.
"Barca returned to training on Thursday with the news of Douglas' fall," read a club statement.
"After taking a hit during the Copa match against Villanovense, tests have shown this morning that the Brazilian has a crack in the scaphoid of his right foot. The estimated downtime will be around eight weeks."
Alongside Douglas, coach Luis Enrique is already without Lionel Messi, Andres Iniesta, Rafinha and Sergi Roberto due to injuries, with Javier Mascherano handed a two-game suspension on Wednesday.
The Argentina international was sent off against Eibar on Sunday for a rant at an assistant referee.
