Italian Sinner, winner of the previous two Six Kings, announced this month that he would not compete again in 2026 as he continued his recovery from a knee injury that has sidelined the 25-year-old since winning Wimbledon in July.
That decision ruled him out of the European indoor hardcourt swing along with the season-ending ATP Finals in Turin where Sinner also triumphed in the last two years.
The lucrative Six Kings Slam exhibition event, a non-ATP tournament, was due to take place in Riyadh from October 21st to 24th, but is now scheduled for December 27th to 30th.
Organisers announced the date change after an attack by Yemen's Iran-aligned Houthis on Riyadh's international airport killed 13 people.
January's Dakar Rally was moved out of Saudi Arabia due to security concerns, and golf's Asian Tour has postponed the Saudi International indefinitely.
Sinner beat Carlos Alcaraz in both Six Kings finals, earning himself $6 million at each event.
Along with Sinner and Alcaraz, the event will also feature Novak Djokovic, Alexander Zverev, Taylor Fritz and Alex de Minaur. Zverev is guaranteed to finish 2026 as the ATP's year-end world number one.