Three people have tested positive for coronavirus at Cologne and will be placed into a 14-day quarantine, the Bundesliga club said Friday in a potential blow to hopes of restarting the German football season this month.
"Cologne had the entire team and coaching staff, along with the backroom staff, tested on Thursday for COVID-19. Three people tested positive, all are symptom free," the club said in a statement on its website.
"After an assessment of the cases by the responsible health authorities, the three people who tested positive will go into a 14-day quarantine at home.
"Cologne will not confirm any names out of respect for the privacy of those affected."
The club said it would continue to train in preparation for the campaign to resume, with further tests to be carried out as part of the league's health and safety protocol.
"We now see in everyday life that our concept recognises and reduces risks at an early stage," said Tim Meyer, head of the German league's medical task force.
"We are convinced that with our concept, we can enable players to practice their profession with the best possible protection against infection."
The Bundesliga had set a target return date of May 9 but still needs permission from the German government.
A delay on the decision this week meant a resumption would not be possible before May 16.
A final decision is expected next Wednesday.
The German league confirmed Thursday that clubs had started testing players for the virus as part of plans to get the season up and running again.
It has been suspended since March 13.
Clubs returned to training at the start of April while adhering to social distancing guidelines and games would be played behind closed doors, with large-scale public events banned in Germany until August 31.