Motherwell defender Declan Gallagher has been called up to the Scotland squad with Ryan Jack and Grant Hanley both out.
The uncapped centre-half, 28, has been outstanding for the Steelmen since joining from Livingston in the summer.
As well as showing off his undoubted ability in winning aerial duels, Gallagher has demonstrated his passing ability, leadership qualities and is a threat in the opposition box from setpiece deliveries.
Gallagher has played his part in seven clean sheets this term for the Fir Park side, who sit third in the Scottish Premiership having won five, drawn one and lost two of their first eight league games.
Steve Clarke’s side face Russia in Moscow on Thursday before hosting San Marino at Hampden on Sunday in Euro 2020 qualifying.