Steve Clarke claims he has experienced the most "disruptive" and "troublesome" period of his Scotland tenure ahead of the World Cup qualifying triple-header.
Midfielders Scott McTominay and Stuart Armstrong were already ruled out of the Group F fixtures against Denmark, Moldova and Austria and they were joined by injured Celtic duo James Forrest and Greg Taylor, who both missed the Hoops' 1-0 cinch Premiership defeat by Rangers at Ibrox on Sunday.
Light Blues right-back Nathan Patterson, along with Aston Villa's John McGinn, who has tested positive for Covid-19, are currently following government guidelines and will not be available for the match against the Danes.
Boss Clarke revealed that set-piece coach Austin MacPhee, who he had just been added to his backroom staff, "has picked up Covid" and will miss the three games with Hearts coach and former Scotland attacker Steven Naismith drafted in to help.
Clarke said: "Two years into my international career it has probably been the most disruptive camp in terms of call-offs, which is disappointing.
"It has been the most troublesome week before a get together, a lot of call-offs, a lot of Covid issues around the place.
"I don't think it is going to get any better because the more society opens up, the more infections are going to go up.
"I think you see that in Scotland with the number of Covid infections, thankfully not so many deaths which is a tribute to the vaccination programme which has worked really well and the more people we can get double jabbed quicker, the better.
"Covid is still out there and it is a big issue for us. But I think I have enough in the current group to go to Denmark and hopefully get the result we all want.
"Medical advice and information tells me that both John and Nathan should join us after the Denmark game, which is good, so I don't have to delve too deep for replacements.
"I will work with a slightly smaller squad for the Denmark game and hope to welcome the two boys back on Thursday morning.
"Everyone who is in the squad is fit and available. Stephen O'Donnell was not involved at the weekend but was available to be involved, he did a training session yesterday and felt good and will be ready for Wednesday night.
"I don't expect any more issues, that's not to say there won't be any more issues."
Former St Mirren, Hearts and Northern Ireland assistant MacPhee was asked to join Clarke's backroom team following the departure of Steven Reid.
The former West Brom and Kilmarnock player said: "I have lost Austin, he hasn't made it to camp, he has picked up Covid.
"We wish him well and a speedy recovery from his Covid. It doesn't just affect players, it affects coaches as well. It is a completely different blow for me.
"I was hoping I would have a new coaching team in place, at the very last minute I asked Steven Naismith – who I know as a player – to step up and become an extra pair of eyes on the training pitch. He will be here for this camp."
Scotland play Denmark away on Wednesday and then host Moldova at Hampden on Saturday night before a trip to Austria next Tuesday.
Clarke's side have five points from three games and sit in second place, four points behind Euro 2020 semi-finalists Denmark.
