Players and staff from Germany's top two divisions have tested positive for the coronavirus in a potential blow to a swift return of the Bundesliga.
And former Chelsea striker Salomon Kalou has been suspended and forced to apologise after flouting social distancing rules at Hertha Berlin.
A total of 1,724 tests have been carried out on players from 36 clubs in the top two tiers of German football since last Thursday. All the 10 individuals have been isolated and a second wave of tests to be conducted this week.
Cologne announced on Friday that two players and a physio had tested positive and sent home but the club said there had been no new cases after more testing.
Kalou has been slammed by the German Football League (DFL) and then suspended after streaming a live video on Facebook showing him shaking hands with staff and team-mates and sitting next to team-mate Vedad Ibisevic. The DFL said the video was “absolutely unacceptable”.
Kalou said: "I am sorry if I gave the impression that I am not taking Coronavirus seriously. I apologise for this.
"The opposite is the case, because I am especially worried about the people in Africa, where medical care there is nowhere near as good as in Germany.”
Bundesliga teams have been back in training since April 6 and Germany's return to action is seen as the role model for the Premier League.
Chancellor Angela Merkel is expected to announce a timetable on Wednesday with the DFL still hoping to stage matches later this month.
