Scotland's Six Nations match against France is in jeopardy after a number of French players and coaches tested positive for Covid-19.
Gregor Townsend's side are due play in Paris on Sunday, but with case numbers rising in home ranks, the fixture may be postponed.
A decision on whether the match can be played will be made on Wednesday by the tournament organisers.
Should it be put back, Townsend will be shorn of a number of key players.
On Tuesday, the French Rugby Federation said there were no more positive cases in the latest round of testing.
France top the Six Nations table after winning both matches so far, while Scotland sit fourth having followed an historic win over England at Twickenham with a one-point home loss to Wales.
What's the situation?
After overseeing his team's victory over Ireland last Sunday, France head coach Fabien Galthie and a member of the non-playing staff tested positive two days later.
From that point on, as more rounds of testing were completed, more positive results were returned.
On Monday, six days after Galthie entered isolation, the tally of positives in the playing squad rose to 10, nine of whom were part of the match-day 23 in Dublin. Star scrum-half Antoine Dupont, captain Charles Ollivon and wing Gabin Villiere are among those now isolating.
Assistant coach William Servat also tested positive.
Players have been called up to replace those now unavailable for Scotland's visit, and team training is due to resume on Wednesday, with testing conducted every 24 hours and no positives recorded in Tuesday's batch.
What are the options?
The Six Nations will decide whether the Test can take place as scheduled, or must be postponed, on Wednesday.
"Ensuring the health and safety of all players and staff is our number one priority," they said in a statement. "Should the decision be that the fixture cannot go ahead, the match will be rescheduled for the earliest possible date."
The "earliest possible date" seems to be the following weekend, a rest week for the tournament outside of World Rugby's designated international window.
But that would pose problems for Scotland. Under World Rugby regulations, their players based in England and France will be released back to their clubs for domestic duty.
That would leave Townsend without a host of front-line players, including captain Stuart Hogg, fly-half Finn Russell, lock Jonny Gray and centres James Lang and Chris Harris. In fact, 11 of the coach's wider squad would be rendered unavailable for an out-of-window Test.
Scottish Rugby released a statement on Monday saying that "any postponement will have an impact on the player release agreement in place with clubs.
"We will be working closely with our Six Nations counterparts to press the case for this week's game to go ahead, should it be medically safe to do so."
What happened in the autumn?
It is worth remembering that, owing to an agreement on player load between the French Rugby Federation and its Top 14 clubs, France were at times forced to pick vastly depleted sides during the recent Autumn Nations Cup.
Missing their entire first-choice XV, they still managed to take full-strength England to extra time in the tournament finale at Twickenham.
That suggests that depth will not be a problem, and that Scotland would still face a significant challenge to earn their first win in Paris since 1999 should the game go ahead as scheduled.
Situation 'plays in France's favour' - analysis
Former Scotland, Castres, Montpellier and Bayonne number eight Johnnie Beattie on BBC Radio Scotland
Strangely, it plays in France's favour. They play a lot on psychology and emotional drivers. You've got nearly a whole XV coming in and now they've got a chance to play a part in a Grand Slam.
Weirdly, because they're all in confinement, missing Galthie doesn't make any difference until they start training together on Wednesday. Shaun Edwards is the world's best defence coach, he knows how to take a training session. Galthie and Servat will be part of every session by FaceTime. Galthie will be in every huddle, leading every team meeting thanks to the technology.
I don't think the game is going to go ahead. I think it's going to be postponed. And I think France will be favourites if it's postponed.
If Scotland get to play against this majorly weakened side, they'll be up against a line-out that hasn't had much time together, a scrum that hasn't had many reps together, so there's a chance to sneak it.
If it gets pushed to next weekend, it becomes a tougher proposition.