Atletico Madrid striker Joao Felix has suffered an ankle sprain.
Felix had to go off injured against Real Betis in the 1-1 draw on Sunday.
Meanwhile his team-mate Kieran Trippier has back pain.
Felix was taken off at the start of the second half after hurting himself in a challenge with Aissa Mandi, while Trippier went off in the 78th minute.
Both players were tested on Monday and Atletico did not specify the length of absence periods.
Felix is expected to miss around 10 days and it leaves the club with only Angel Correa fit up front. Luis Suarez is injured and winter signing Moussa Dembele is out too.
