Celtic could be missing key pair Kyogo Furuhashi and Tom Rogic for their rescheduled derby clash with Rangers.
The Glasgow rivals will now face off on Wednesday, February 2, after the Scottish Premiership winter break was brought forward.
The showpiece clash was scheduled for January 2 but two rounds of fixtures have been rearranged due to surging Omicron cases.
But that could mean a knock-on effect for Ange Postecoglou's side in their push for the title.
Talisman Kyogo is set to be called into the Japan squad for the crucial World Cup qualifier with Saudi Arabia.
Japan currently sit in second spot in Group B and face the group leaders on February 2 - the same day as Celtic are set to host Gio van Bronckhorst's side.
And Postecoglou is keen to recruit J-League trio Reo Hatate, Daizen Maeda and Yosuke Ideguchi in January with Maeda and Hatate in the mix to be called up.
Travel restrictions had previously forced Japan to select from J-League talent for games, however eased restrictions increase the likelihood of a call-up.
JFA president Tashima has previously stated they would only call on players in line with government guidance.
Similarly, Rogic will be needed by Australia for their crucial double header as they look to overtake Japan and Saudi Arabia.
The playmaker will definitely be in Graham Arnold's thoughts for the games against Vietnam and Oman, as the Socceroos face a battle to qualify.
It gives Postecoglou a major selection headache to plan for going into one of the biggest games in the calendar.
