Scotland have called up wingers Gary Mackay-Steven and Craig Conway for their friendlies against the United States and Norway.
The Scottish Football Association had earlier confirmed that Celtic's James Forrest and Birmingham wide man Chris Burke had pulled out ahead of Friday night's Hampden clash with the USA.
Conway won the last of his five caps when he came on as a substitute during Scotland's 3-2 defeat by England at Wembley in August.
The 28-year-old moved from Cardiff to Brighton soon after that game and has played regularly in recent weeks.
Former Scotland Under-21 player Mackay-Steven has been in several squads but has yet to make his full international debut.
The 23-year-old was on top form as Dundee United won 4-0 at Motherwell on Saturday.
Forrest went off with an unspecified injury during Celtic's 4-1 win at Ross County on Saturday. He last played for Scotland in the 2-0 defeat by Belgium in September after being troubled by sciatica during the early part of the season.
Burke came off with an ankle injury during his side's weekend clash with Huddersfield.