Two players at German second division side Dynamo Dresden have tested positive for coronavirus, putting on hold the club's planned return to Bundesliga 2 action next weekend.
Dresden were due to play Hannover away on May 17 when the league resumes after a two-month suspension, but the entire squad, coaching and supervisory staff must go into 14 days of quarantine at home.
"We are in contact with the responsible health authorities and the league to coordinate all further steps," Dynamo sporting director Ralf Minge says.
"The fact is that we can neither train nor participate in any games over the next 14 days."
The players, who have not been identified, had their positive results for COVID-19 found in a third wave of tests conducted at the club on Friday as part of the league's hygiene protocol to get football back underway in Germany.
One player tested positive for COVID-19 in the first wave of tests last weekend. He has been in quarantine since May 3. There were no positive cases in the second wave on May 4. The team returned to full training on Thursday.
Chancellor Angela Merkel had announced the day before that the top two divisions could resume without spectators. Teams were to spend time training in isolation before the games could resume. The Bundesliga and second division are due to return on May 16.
Dynamo say the two players who tested positive on Friday did not and are still not showing any symptoms of the virus.
'Players need to be disciplined in virus plan'
Each individual player's behaviour will be "crucial until the end of the season", the medical head of the Bundesliga and UEFA's efforts to restart the game across the continent warned on Sunday.
Tim Meyer, the head of the Bundesliga's new coronavirus task force and chairman of the UEFA medical committee, said that while the German league had produced the safest possible system for resuming competition, it was vital that players showed discipline and kept to the new rules.
"Football has to give something back to the people now," he said. "That also means to be disciplined as a player. Keeping themselves away from the virus and the virus from them is the target. They need to be responsible.
"They are very public and need to show how to behave - on the pitch, play football as always but as soon as you leave the pitch, you are a citizen again and need to behave as a citizen in times of coronavius," he added.
Meyer said his task was to create the highest possible level of safety, based on what was "medically justifiable".
"We do not think that any job, any profession in the country is 100 per cent safe at this moment, as long as you deal with other human beings," he said.
"Sometimes there are people who say, 'there is still a little risk'. Yes there is. We will not be able to eliminate any small risk - we did a lot, we put a lot of measures in place, to make sure that infections from football are highly unlikely."
Sunday Supplement: 'Issues will come up every single day'
Analysis from The Mirror's chief sports reporter Andy Dunn...
"I don't think the Bundesliga and Brighton cases are game-changers. They are just indicative of the type of hurdles that are going to have to be surmounted if you want to get football back on.
"Talking about Germany, there were three players from Cologne, at the start of the month, who tested positive for coronavirus, yet they still carried on training. The local health authority gave them permission and they are scheduled to resume their Bundesliga season against Mainz next Sunday.
"Local health authorities in different regions of Germany are reacting differently. Clearly in the case of the latest Brighton player to test positive, they won't have resumed team training yet, obviously, so it might be that he just has to self-isolate.
"These are all problems and barriers that we know are going to be put up. Without doubt we know they are going to be put up and they are going to be tough to get over, but you mention asking the question to Dominic Raab, the reason why No 10 asked a sports reporter to ask a question at that briefing, was because they want to get out there.
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"He was ready to say that they want it to come back, they want it to lift the spirit of the nation, which Culture Secretary Oliver Dowden repeated on Friday, and it's quite clear from the feedback we are getting from the government that they want this to go ahead, and the Premier League, for financial reasons, want it to go ahead.
"Basically, the will is there from the government and from football to get it back on. They know they are going to have issues like this that are going to come up every single day. Last night the Bundesliga, today the Brighton issue and they are going to have to be got over.
"Whether or not these hurdles can be surmounted remains to be seen, but the underlying point, certainly from the government this week, is that they will do all they can to help the Premier League get this back on."