Despite rigid hygiene guidelines for the restart of the Bundesliga this weekend, a leading German sports doctor has warned footballers are still at risk of suffering "irreversible" and potentially career-ending lung damage from the coronavirus.
With Europe's other top leagues at least a month away from resuming, the German Football League (DFL) has drawn up strict rules for when games restart this Saturday.
Matches will be played behind closed doors, with only a limited number of media and officials allowed to attend.
The key games see second-placed Borussia Dortmund at home to Schalke in Saturday's derby and leaders Bayern Munich, who are four points clear, visiting Union Berlin on Sunday.
Players have been told to limit contact, even on the pitch, and must avoid pre-match handshakes and hugs to celebrate goals.
The DFL says while no plan could ever be "100 percent safe", the guidelines aim to create a playing environment with a low, "medically-justifiable risk".
However, professor Wilhelm Bloch, from the German Sports University in Cologne, warns that contracting the coronavirus has the potential to end a player's career.
"There is a risk that top athletes may lose their level of performance and never regain it," Bloch told AFP in a phone interview.
"Generally, the physical makeup, immune system and cardiovascular system of elite athletes means that the risk to them is low.
"However, we do not know at this time whether even minor infections, or even mild symptoms, do not cause damage, such as minor scarring of the lungs after an inflammation.
"This damage may be irreversible, or may last a very long time before the body repairs it.
"We've already had players infected in Europe and we'll soon know if they recover their full potential."
- Increased injury risk -
Bloch said it is near impossible to estimate what the risk is to footballers in Germany, which currently has 172,239 recorded cases of the virus and over 7,700 deaths.
"Players are not in total quarantine, they are with their families, even if they have been instructed to limit contact," he said.
"And there are also risks during matches.
"They will all be tested, but not all the coronavirus tests work perfectly. There is a relatively large margin of error."
The sports doctor says another concern is injuries to players, given their lack of match fitness since the league stopped in mid-March.
"Obviously, the players are not optimally prepared," Bloch said, with clubs only resuming full team training last week.
"Depending on the degree of preparation, the risk of injury increases.
"We can expect that the players will be more prone to injuries.
"We will see muscle injuries, but also injuries to the musculoskeletal system and tendons.
"You can't compare it with the start of the season.
"At the beginning of the season they normally have a very intensive training period, then a short break so that the body can regenerate, and then they attack the season.
"Now, that hasn't been possible for all the teams."
Bloch also wonders how players can be expected to throw themselves into tackles after weeks of being told to observe social distancing.
"I'm not a psychologist, it's difficult to assess, but I think it's going to be a difficult transition and it won't necessarily be good for their performance," said Bloch.
"It's also going to be one of those factors that you have to consider and one of the risk factors for injury."