No prizes for guessing what Neil Lennon would have been thinking as he sent his players away to meet up with their national teams eight days ago.
Number one priority for the Celtic boss would've been to see all of his key men return from the international break fit, healthy and ready to star in their biggest match of the season to date. So, to put it mildly, you can bet he'll be less than satisfied with what this week or so has thrown up. Three key men are currently self-isolating and a fourth awaiting the results of a COVID-19 test.
Ryan Christie and Nir Bitton are both out of Saturday's Old Firm match, while Odsonne Edouard and Hatem Abd Elhamed are clearly doubts. Edouard tested positive for COVID and he's required to self-isolate in France until the end of this week, while Elhamed is struggling with illness.
Add to this recent injury concerns over Albian Ajeti, and Lennon has some tough choices to make so far as his team selection for this weekend goes.
James Forrest and Mikey Johnston are, of course, also out as they recover from longer-term problems.
However the Celtic boss couldn't have imagined when the final whistle went at McDiarmid Park that he'd be planning with his next fixture without Christie, Bitton and potentially Elhamed, Edouard and Ajeti.
So – should Celtic's worst case scenario come to fruition and all five men are ruled out – how will the team look?
Well you'd imagine the starting defensive positions are unaffected. Jeremie Frimpong and either Diego Laxalt or Greg Taylor were likely to start in wing-back positions, while Lennon's first choice back three is Shane Duffy, Kris Ajer and Christopher Jullien.
However without Bitton and Elhamed as back-up Celtic could be light on options should they wish to switch things up, or in the event of an injury.
On paper a midfield three of Scott Brown, Callum McGregor and Olivier Ntcham looks far from weak, and with Tom Rogic and David Turnbull in reserve Celtic still have options to choose from.
In attack Christie, Edouard and Ajeti's potential absences leaves just Leigh Griffiths, Patryk Klimala and Moi Elyounoussi.
A front-two of Griffiths and Elyounoussi could perhaps be Lennon's favoured choice given Klimala's relative inexperience in Old Firm fixtures
So, while the COVID-19 situation will almost certainly give the Hoops boss a selection headache, there's no doubt he still has a strong squad to choose from.
Rangers could also be without a number of important players too. Joe Aribo and Kemar Roofe are recovering from injury and unlikely to make it while Borna Barisic and Filip Helander are struggling with slight knocks. Niko Katic remains out long-term.
We at Glasgow Live will ask Rangers and Celtic supporters to name their Old Firm derby starting XI later this week.
