The goalkeeper, who was at Celtic when Gordon Strachan was in charge there, has been given a chance while No 1 Allan McGregor is out with a thigh injury.
Sunderland's Steven Fletcher is also in the squad after losing his place due to an ankle injury, and QPR winger Matt Phillips has been recalled after recovering from a broken arm.
Gordon Strachan, the Scotland manager, said: "I take into consideration what Jim Stewart, the goalkeeping coach, says but in the games I have seen going to watch Partick Thistle live, he has made some big saves.
"He was one of the Celtic youngsters who wanted to go out and play. Scott went on loan to East Fife, he was desperate to play. His attitude has got him where he is today."
Fox, 26 years old, left Parkhead in 2010 and joined Thistle later the same year after brief spells with Queen of the South and Dundee.
Fletcher has not played for Scotland since suffering an ankle injury in the opening minutes of the 2-1 World Cup qualifying defeat by Wales at Hampden on March 22.
His return was delayed by a dislocated shoulder but he has played the last three games for Sunderland and scored in the derby win over Newcastle last month.
Strachan said: "He can add to what we have been doing already and if he surpasses what the boys have been doing up front in recent games, that will be terrific.
"It will take him a wee while to get back to his best. If he's not back to his best, we can wait a bit because the other players playing up front now are playing quite well."