Atletico Madrid say forward Mario Mandzukic could make his return from a fractured nose in around 10 days but will have to wear a protective mask.
The 28-year-old underwent an operation on Thursday after suffering the injury in Tuesday's 3-2 Champions League defeat at Olympiakos.
"Normally he would be available to play in 15 days but with a mask he could do so in 10," Atletico doctor Pedro Luis Llopis said.
"He will have a personalised mask."
Croatia striker Mandzukic has scored two goals in four competitive games since signing for La Liga champions Atletico from German champions Bayern Munich for an undisclosed fee in July.
But he will miss Saturday's La Liga game at home to Celta Vigo as well as Wednesday's trip to Almeria.
However, Mandzukic should be back for the Champions League group match at home to Italian champions Juventus on 1 October.