Bayern Munich said Friday that full-back Noussair Mazraoui tested positive for the coronavirus during Morocco's historic run to the semifinals of the World Cup and has since been found to have swelling around his heart.

Bayern left Mazraoui out of the squad that left on Friday for a winter training camp in Qatar ahead of the Bundesliga season resuming on Jan. 20, citing the inflammation.

The club said Mazraoui tested positive for COVID-19 while at the World Cup in early December and that was the reason he didn't play in Morocco's quarterfinal win over Portugal.

His absence was widely attributed to an unspecified illness at the time. Mazraoui returned to play the first half of the semifinal loss to France as Morocco became the first African and Arab team to reach the last four of the World Cup.

Bayern said an examination in Munich after the tournament found a “mild inflammation" and that Mazraoui is not available to play “for the time being.” This kind of inflammation is a known complication of COVID-19 infection.