Scotland right-backs Nathan Patterson and Aaron Hickey will both definitely miss Euro 2024, according to assistant manager John Carver.
Patterson was told he needed surgery after suffering a hamstring injury while playing for Everton against Chelsea last month.
Brentford full-back Hickey also suffered a hamstring injury at Stamford Bridge and has not played since October.
Confirmation of the double blow comes after Lewis Ferguson was ruled out of the tournament after suffering cruciate ligament damage.
When asked whether Hickey would be missing, Carver told STV: "You can also throw Nathan Patterson from Everton into that as well.
"It's three big players for us and three players who have done extremely well for us in the qualifiers and in recent times
"The good thing is they are three young lads who hopefully have World Cups and Euros to come in the future, so we won't forget about them."
The double blow creates at least one vacancy in Steve Clarke's squad with Celtic's Anthony Ralston the only other right-sided wing-back in the pool for last month's friendly defeats against the Netherlands and Northern Ireland.
Versatile Bristol City player Ross McCrorie, who has featured at right-back in his career, was also a late call-up recently.
Stephen O'Donnell and Celtic winger James Forrest have both played in the wing-back position for Scotland but the Motherwell player has not been in a squad for two years, while Forrest last featured at the previous European Championship three years ago.
Carver recently attended Aberdeen's 4-0 win over Hibernian where Nicky Devlin and twice-capped Chris Cadden featured at right-back, although he was reportedly watching Dons midfielder Connor Barron.
