Craig Halkett has performed well in a back three for Hearts this seasonSunderland's Ross Stewart and Hearts' Craig Halkett have been called up by Scotland for the first time.
St Johnstone goalkeeper Zander Clark will also join the squad to replace the injured David Marshall.
Stewart has scored 22 goals in 38 games for the English League One side this season.
Halkett will cover central defence after Scott McKenna withdrew, with Liam Cooper and John Souttar sidelined.
Both first-time call ups could make their debut in the friendly with Poland on Thursday, with Scotland then playing either Austria or Wales the following Tuesday.
Meanwhile, captain Andy Robertson is a doubt after missing Liverpool's FA Cup quarter-final win against Nottingham Forest with illness.
Stewart played for Ayrshire junior clubs Ardeer Thistle and Kilwinning Rangers after several years in the pro youth system with St Mirren, Celtic and Partick Thistle.
He then earned a move back to the senior game with Albion Rovers and had stints with St Mirren and Alloa Athletic before coming to prominence with Ross County, where he scored 28 times in 82 appearances to earn a move south.
Stewart on rediscovering his love of football playing juniors
"I broke my nose that day. I can just remember being sparked out and getting called all the names under the sun. There was blood everywhere, my nose was pointing sideways, and you're getting called a 'diving you-know-what' and all that." Read more.
Halkett has been a key member of the Hearts back three which has performed strongly to help the Tynecastle side to third in the Scottish Premiership.
Scotland are playing the Poles instead of their postponed World Cup play-off semi-final against Ukraine.
The game will be played at Hampden with £10 from each ticket sold going to Unicef's response in Ukraine following Russia's invasion of the country.
The Scottish FA has announced 25,000 tickets have been sold already for the match.
Poland had been scheduled to play the Russians on 24 March, but have been given a bye into a final with Czech Republic or Sweden on 29 March.
Scotland and Ukraine hope to meet in June, with the winners facing either Wales or Austria.
Those two sides meet in Cardiff on Thursday, with the losers hosting Scotland in a friendly on 29 March.
Scotland squad
Goalkeepers: Craig Gordon (Hearts), Liam Kelly (Motherwell), Zander Clark (St Johnstone).
Defenders: Grant Hanley (Norwich), Jack Hendry (Brugge), Craig Halkett (Hearts), Aaron Hickey (Bologna), Stephen O'Donnell (Motherwell), Nathan Patterson (Everton), Andy Robertson (Liverpool), Greg Taylor (Celtic), Kieran Tierney (Arsenal).
Midfielders: Stuart Armstrong (Southampton), Lewis Ferguson (Aberdeen), Billy Gilmour (Norwich, on loan from Chelsea), Ryan Jack (Rangers), John McGinn (Aston Villa), Callum McGregor (Celtic), Kenny McLean (Norwich), Scott McTominay (Manchester United).
Forwards: Che Adams (Southampton), Jacob Brown (Stoke), Ryan Christie (Bournemouth), Ross Stewart (Sunderland).
