Manchester United midfielder Scott McTominay was one of six players handed their maiden Scotland call-ups as manager Alex McLeish named the first squad of his second spell in charge.
McTominay, Barnsley striker Oli McBurnie, Wolves left-back Barry Douglas, Hearts goalkeeper Jon McLaughlin, Hibernian midfielder Dylan McGeouch and Aberdeen defender Scott McKenna are all included.
McTominay was eligible to play for both England and Scotland with both eager to bring him into their international set-ups. The 21-year-old midfielder qualifies for Scotland through his father and opted to play for McLeish's men.
Sky Bet: Scott McTominay is 9/2 to score anytime in Manchester United v Porto on Tuesday night
McLeish has also selected three more uncapped players for the friendlies against Costa Rica and Hungary later this month - Millwall goalkeeper Jordan Archer, Rangers winger Jamie Murphy and Fulham midfielder Kevin McDonald.
Russell Martin returns to the squad after joining Rangers earlier this year and Fulham’s captain Tom Cairney is also recalled, alongside Matt Richie who scored for Newcastle United in the victory over Southampton on Saturday.
Ryan Christie, Jason Cummings and Matt Phillips all keep their places in the squad after featuring in the defeat to the Netherlands at Aberdeen's Pittodrie Stadium back in November.
The match against Costa Rica will be the first time the two sides have met since Costa Rica secured a 1-0 victory in the 1990 FIFA World Cup, Juan Cayasso scoring the solo goal in a game that was the only time these two sides have faced each other previously.
Scotland will then travel to Budapest, where they will face a Hungary side currently sat in 54th in the FIFA World Rankings.
Scotland squad in full for friendlies v Costa Rica and Hungary
Goalkeepers
Jordan Archer (Millwall)
Alan McGregor (Hull City)
Jon McLaughlin (Heart of Midlothian)
Defenders
Barry Douglas (Wolverhampton Wanderers)
Grant Hanley (Norwich City)
Russell Martin (Rangers, on-loan from Norwich City)
Scott McKenna (Aberdeen)
Charlie Mulgrew (Blackburn Rovers)
Callum Paterson (Cardiff City)
Andy Robertson (Liverpool)
Kieran Tierney (Celtic)
Midfielders
Stuart Armstrong (Celtic)
Tom Cairney (Fulham)
James Forrest (Celtic)
Ryan Fraser (Aberdeen)
Kevin McDonald (Fulham)
Dylan McGeouch (Hibernian)
John McGinn (Hibernian)
Calum McGregor (Celtic)
Kenny McLean (Aberdeen, on-loan from Norwich City)
Scott McTominay (Manchester United)
Jamie Murphy (Rangers, on-loan from Brighton and Hove Albion)
Matt Ritchie (Newcastle United)
Forwards
Ryan Christie (Aberdeen, on-loan from Celtic)
Jason Cummings (Rangers, on-loan from Nottingham Forest)
Oliver McBurnie (Barnsley, on-loan from Swansea City)
Matt Phillips (West Bromwich Albion)