Atletico Madrid's Diego Costa and Santiago Arias have tested positive for coronavirus, the club announced on Thursday.
The Spanish club said both are asymptomatic and currently isolating.
"Today, tests were carried out at the Wanda Atletico de Madrid Training Complex prior to resuming the 2020/21 season. The team has been tested except for those involved in international fixtures with their countries," the club said in a statement.
"Diego Costa and Santiago Arias, who tested positive during their holidays, are currently isolating and show no symptoms. Both players are staying at home complying with all protocols and measures set by the authorities and LaLiga," it added.
Atletico Madrid said that both the players will not resume training on September 4 and their return is "expected after completing their quarantine."