Atletico Madrid's coronavirus headache worsened on Wednesday when Lucas Torreira joined Uruguay team-mate Luis Suarez in testing positive.
The Celeste's most recent qualifiers, which ended with victory over Colombia followed by home defeat at the hands of Brazil, have been overshadowed by an outbreak of the pandemic disease within the squad.
Suarez and left-back Matias Vinas were ruled out of the clash with Brazil after testing positive on Monday, while defender Alexis Rolon and forward Diego Rossi as well as several members of Oscar Tabarez's backroom staff joined them in returning positive PCR analyses 48 hours later.
Suarez also saw his positive test confirmed on Wednesday, meaning that he will be unable to take part in the weekend fixture against Barcelona and thus misses his first reunion with his former team-mates since leaving Camp Nou for the Wanda Metropolitano over the summer.
Torreira, who played against Brazil but was found to be carrying the virus upon his return to Madrid, will also be forced to isolate and will not be able to take the field.
"Lucas Torreira underwent PCR tests on Wednesday upon arrival in Madrid after returning from international duty with Uruguay, following the usual protocol when our international players return after their national teams’ commitments," Atletico confirmed in a statement published on the club's official website.
"The midfielder has tested positive for Covid-19.
"The footballer is asymptomatic and isolating at home, in compliance with the health authorities’ quarantine protocols."
Atletico's woes during the international break continued on Tuesday when they learned of an injury to Mexico midfielder Hector Herrera, who had been in fine form for Diego Simeone's charges prior to the recess.
Herrera suffered a thigh injury in training for El Tri and is expected to miss several weeks while he recovers, leaving the Colchoneros severely hamstrung for Saturday's clash against Barcelona.
The club currently sits third in the Liga standings after seven matches, three points behind leaders Real Sociedad having played two games fewer and no less than six ahead of lowly Barca, who languish in 11th.