The Scots had been preparing for Friday's World Cup qualifier away to Moldova (kick-off 17:00 GMT) at a training camp in Spain, but illness has forced the Manchester United midfielder to withdraw from the squad.
However, the Reds' no.39 could yet feature in the subsequent match for Steve Clarke's team, against Denmark on Monday, if he is able to overcome the virus in time.
Ahead of the Moldova game, the Scotland boss clarified the United player's situation.
“Unfortunately, Scott McTominay has picked up a bit of a throat virus,” confirmed Clarke. “We have sent Scott home to rest and recuperate.