Filipe Luis is set for a spell on the sidelines after suffering a thigh injury during training on Wednesday, Atletico Madrid have announced.
The left-back has been a mainstay in Atletico's defence under Diego Simeone, playing 18 of their 20 matches in all competitions this season.
He sat out Tuesday's 1-0 defeat to Bayern Munich in the Champions League with Atleti's progress to the last 16 already secured and a day later he suffered a grade two tear in his left thigh.
Tests conducted on Thursday confirmed the tear, but Atleti did not confirm how long he will be out for.