Sunderland head coach Lee Johnson has revealed 13 of his players have tested positive for Covid-19 including all three of his goal keepers.
The Black Cats are scheduled to face Accrington Stanley on December 29, but fate of that fixture depends on how the players affected by coronavirus recover.
Johnson has revealed not all of those who tested positive displayed symptoms and four players who are isolating will only be able to stop isolating on the day they're set to face John Coleman's Accrington.
Speaking to the #SAFCUnfiltered podcast, Johnson said: "It's been a tough moment for us, it's definitely been a hurdle.
"I think we've ended up with about 13 players testing positive for COVID-19. Not all of those have had symptoms.
"A couple of those struggled, in terms of it's taken longer than they had hoped to get over. We're just monitoring them all as much as possible, and obviously our thoughts are with them and their families because for a couple of them, their families have picked it up as well.
"It's been tough because it's unprecedented times and we just don't know it's going to affect their lung capacity or anything else moving forward. "
The Black Cats have postponed three of their League One fixtures as a result of the outbreak, and Johnson said that the Accrington game may also be postponed.
Johnson said: "It depends on when we get back to action.
"First and foremost, our three goalkeepers have all tested positive. So that's leaves us in a bit of a pickle, depending on how we recover.
"One in particular has struggled quite a lot and the health and wellbeing of a player has to be at the front of any decision that is made.
"We've also got four senior players who are only able to come out of their isolation on the matchday of the 29th.
"So there's no way they can prepare or train, other than that at home.
“We've had to give them online sessions to do on zoom, which has been interesting and actually really good.
"But we've also done a lot of tactical work online as well, presented some slides just to see what their understanding is of the terminology and what we're trying to coach. I've been very impressed with the players on that front.
"It's going to be a very difficult period for us in terms of trying to gain any kind of consistency, but at the same time, we're doing everything in our control to try and achieve that."
