Atletico Madrid said that Portugal forward Joao Felix has twisted his right ankle during Saturday's Spanish league match against Valencia.
Felix went down with around 10 minutes left in the game when his ankle buckled and had to be helped off the field.
That left Atletico with 10 men and Valencia soon leveled to take a 1-1 draw. The club did not say how long it expected him to be out.
Atletico broke their club record for a transfer to sign Felix from Benfica this summer after triggering the €126 million ($140 million) buyout clause in his contract.
The 19-year-old has scored three goals for Diego Simeone's team.
Source: espn.co.uk