Celtic and Hibs could be without key players for their derby matches at the end of December after Australia’s Asian Cup squad was announced.
Celtic playmaker Tom Rogic has been called up by the Socceroos, while Hibs trio Martin Boyle, Jamie Maclaren and Mark Milligan have also found a place in the 24-man unit.
The Socceroos first game will take place on January 6, eight days after Celtic travel to Rangers and Hibs host rivals Hearts in their final match before the winter break, but Australia coach Graham Arnold wants his squad to meet in the host country, the United Arab Emirates, on December 26.
It is unclear at this stage whether the clubs will be granted special dispensation to keep their talented stars for the Saturday, December 29 fixtures, which take place three days after the planned meet-up for the Australia squad. They will almost certainly be permitted to play in their Boxing Day games.
An Australian Football Federation spokesman told BBC Scotland: “This [December 29] is two days over the Fifa regulation and has been communicated with all clubs.
“It ensures some players get an extra game in for their clubs and enjoy Christmas with their families and friends at home.”
Should Australia suffer an early exit from the tournament – which is unlikely – the foursome may not miss any significant action in 2019.
The final group game is on January 15, four days before the Scottish Cup weekend and over a week before the first league game after the winter break.
However, if Australia are able to reach the final on February 1 then the four players will miss league fixtures in January and another in early February. Hibs take on Motherwell, St Mirren and Aberdeen, while Celtic have four league matches in that time - St Mirren, Hamilton and St Johnstone (twice).
The two clubs will then meet each other at Parkhead on February 6.
Australia are the current holders of the tournament and have reached the final on each of the past two occasions. They are, however, placed as fourth favourites in the eyes of the bookmakers, behind Japan, Iran and South Korea.