Darren Fletcher, James McArthur and James Morrison are also unavailable for the double-header, but Strachan does not see any reason to be concerned as a number of other midfield players are hitting form.
"They're three good players missing, but it's a strong area for us," he told reporters. "We've added Callum [McGregor], who scored two at the weekend, John McGinn, who scored two at the weekend and was fantastic, and Barry Bannan, who was magnificent at the weekend with his team.
"That shows how strong we are and from there we could probably add another three or four midfield players. We're OK there."
Striker Leigh Griffiths only trained briefly on Monday afternoon, meanwhile, but Strachan says that it was not injury related.