Brazilian endures serious damage following injury in training as Spanish club loses another striker for the upcoming campaign
Marca claims the 22-year-old Brazilian forward's right knee buckled during training on Wednesday night.
The player was taken to the Fremap clinic where he underwent a scan to determine the extent of the injury, and the results showed Costa ruptured his cruciate ligament in his right knee.
He will likely miss between six and seven months of the campaign as surgery is required on the injury.
Atletico will be in Europa League action later on Thursday night when they take on Stromsgodset in the third qualifying round.