Watch Denmark vs Scotland live on 7pm on Wednesday September 1, kick-off 7.45pm; Armstrong has suffered a calf issue which will sideline him for Southampton's Premier League game with Newcastle and World Cup qualifiers against Denmark, Moldova and Austria
Stuart Armstrong has withdrawn from Scotland's squad for their fixtures over the international break because of a calf injury.
It follows confirmation earlier from Southampton boss Ralph Hasenhuttl during a press conference on Thursday that Armstrong has picked up a calf problem, which saw him miss the 8-0 demolition of Newport County in the second round of the League Cup.
Hasenhuttl said: "Stuart is not yet back training on the pitch so it will take a little bit longer [than their weekend clash with Newcastle], I think."
The 29-year-old had been called up alongside Saints team-mate Che Adams in Steve Clarke's squad for their triple-header next month.
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Armstrong holds 28 caps for his country and played in all three of Scotland's games at the Euros earlier this summer
He was named on the bench for Southampton's first game of the season, a 3-1 defeat to Everton at Goodison Park, and was not in the matchday squad for the 1-1 draw at St Mary's against Manchester United.
Armstrong's fellow central midfielder Scott McTominay is also absent, having picked up an injury at the start of the season for Manchester United, while Andy Robertson and Kieran Tierney have returned to the Scotland fold.
Norwich's Kenny McLean has also made a comeback after missing Euro 2020, while Zander Clark of St Johnstone and Liam Kelly of Motherwell have replaced David Marshall and Jon McLaughlin.