It's a key test for some of the trickier areas of Russia's preparations, including the costly and much delayed 69,000-seat St. Petersburg stadium.
Russian President Vladimir Putin told FIFA president Gianni Infantino on Friday that the stadium would be finished by the end of next month.
The Confederations Cup's future after 2017 is uncertain, with Infantino saying earlier Saturday that the format could be changed and "we are putting everything on the table."
That's because the 2022 World Cup in Qatar will be held in November and December, meaning the Confederations Cup would cause severe disruption to the club calendar if held in its traditional slot a year before the bigger tournament.
Infantino said FIFA officials are discussing questions such as "Shall we play it in June? Shall we play it in November? Shall we think about the format?"
Last year, then-FIFA secretary general Jerome Valcke said the 2021 tournament would be moved from Qatar and played elsewhere in Asia.The Confederations Cup features many of the best teams in world football - with FIFA's six continental champions, plus the World Cup holder and the following year's World Cup host.
But it has struggled to build a distinct identity beyond being simply a test event for a larger tournament.