Swansea left-back Stephen Kingsley is among four players drafted into the Scotland squad for friendlies against Italy and France.
Derby midfielder Craig Bryson and goalkeepers Scott Fox and Jack Hamilton have also been called up.
Dundee goalkeeper Scott Bain has pulled out while Hull players Allan McGregor, Andy Robertson, Robert Snodgrass and Shaun Maloney, plus Sheffield Wednesday midfielder Barry Bannan, have had to withdraw after getting to the Sky Bet Championship play-off final.
Kingsley and Hamilton are Scotland Under-21 regulars while Ross County number one Fox has previously made the squad under his former Celtic manager Gordon Strachan.
Hamilton has only made eight first-team appearances for Hearts but has just signed a new three-year contract and has featured for Stenhousemuir, Forfar, East Stirlingshire and East Fife on loan.
Kingsley has made his first-team breakthrough at Swansea in recent months, playing four times. The 21-year-old made more than 100 appearances for Falkirk as a teenager and also has first-team experience on loan with Yeovil and Crewe.
Former Clyde and Kilmarnock midfielder Bryson, 29, has won two Scotland caps, the first in a 3-0 friendly win over the Faroe Islands in 2010 and his second in a 1-0 victory in Norway three years later.
There could be more changes in the coming days as Rangers manager Mark Warburton has hinted he will withdraw Lee Wallace and Barrie McKay if his team win the William Hill Scottish Cup and secure an early start in Europe. Fellow cup finalists Hibernian could re-examine John McGinn's place in the squad if they claim the trophy.
Strachan rested Celtic and Aberdeen players and offered Hearts the same privilege in recognition of their European demands.
Scotland face Italy in Malta on May 29 before taking on France in Metz six days later.
Source: PA
