Former England Under-21 cap Jay McEveley has been named in Archie Knox's first squad since being appointed Scotland youth teams coach.
Archie Knox is Scotland's new youth teams coach
Scotland face Slovenia in a European Championships qualifier on 16 August.
The Liverpool-born Blackburn Rovers defender, who qualifies for Scotland through his Dumfries-born grandfather, has elected to change allegiances.
Hearts defender Christophe Berra is suspended as Knox teams up with Maurice Malpas for the first time.
Three of the Under-19 squad that reached the European Under-19 Championships final before losing narrowly to Spain are included in the squad.
Hearts striker Calum Elliot, Hibernian forward Steven Fletcher and Celtic defender Scott Cuthbert could all play in Slovenia.
Knox has called up an extended 26-man squad as he aims to assess the players for this game and the home qualifier against France on 1 September.
Scotland Under-21 squad
Goalkeepers: David Marshall (Celtic); Craig Samson (Ross County); Iain Turner (Everton)
Defenders: Kirk Broadfoot (St Mirren); Scott Cuthbert (Celtic); Alexander Diamond (Aberdeen); Richard Foster (Aberdeen); Alan Hutton (Rangers); Jay McEveley (Blackburn Rovers); Paul Quinn (Motherwell); Steven Smith (Rangers); Steven Whittaker (Hibernian)
Midfielders: Charlie Adam (Rangers); Scott Brown (Hibernian); Paul Lawson (Celtic); Charles Mulgrew (Celtic); Rocco Quinn (Celtic); Kevin Thomson (Hibernian); Ross Wallace (Celtic); Mark Wilson (Celtic)
Forwards: Craig Beattie (Celtic); Darryl Duffy (Hull City); Calum Elliot (Heart of Midlothian); Steven Fletcher (Hibernian); Ross McCormack (Motherwell); Steven Naismith (Kilmarnock)