Cahill spared Socceroo duties due to injury
Cahill and defender Mark Milligan, who plays his club football in Japan and was also excused, will not be replaced in the squad for Wednesday's friendly in Ljubljana.
"After consultation with the players and their clubs after the weekend, acting... head coach Han Berger decided they would not be required in camp," said the FFA release.
Cahill, who played 45 minutes of Everton's last pre-season friendly against German club Wolfsburg at the weekend, had a shortened post-season break after representing his country at the World Cup finals in South Africa.
Everton open their Premier League campaign at Blackburn Rovers on Saturday.