The withdrawal of third-ranked Osaka means Roland Garros will be missing two of the world's top three, after reigning champion Barty said earlier this month that she wouldn't return to defend her title.
Osaka is expected to compete for Japan in next year's Olympics and, like many athletes, may want to use that stage to deliver her message; in Osaka's case, the Black Lives Matter campaign.
US Open 2020: Fourth time's the charm for Dominic Thiem, Naomi Osaka builds on and off the court, and more talking points
US Open 2020 crowned a first-time champion in Dominic Thiem and a third Grand Slam winner in Naomi Osaka in the bubble in New York.
Naomi Osaka defeats Victoria Azarenka in US Open 2020 women's singles final to record third Grand Slam title
Osaka, who had won the same tournament two years ago, bounced back after losing the first set to beat Azarenka 1-6, 6-3, 6-3 in the US Open 2020 women's singles final.
Japanese Prime Minister Shinzo Abe was among those who congratulated Osaka after her victory over Victoria Azarenka in the US Open 2020 women singles final.
US Open 2020: Victoria Azarenka in pain after losing in final but vows to fight for more Grand Slams
Victoria Azarenka lost to Japan's Naomi Osaka in three sets at Flushing Meadows on Saturday in her first appearance in the final of a tennis major in seven years.
Naomi Osaka wore different masks honoring victims of systemic racism and police brutality in the United States in each of US Open's seven rounds.
US Open 2020: Naomi Osaka first in 26 years to come from set down in final to win title, other stats
Naomi Osaka added to her 2018 US Open and 2019 Australian Open trophies with the three set win against Victoria Azarenka. Check out the stats from the match in Firstpost's stat roundup!
US Open 2020: 'Naomi Osaka is special', Twitter reacts to Japanese World No 9's comeback win in final
Check out some of the best twitter reactions to Naomi Osaka's incredible come-from-behind victory over Victoria Azarenka in the US Open 2020 final.
US Open 2020: Naomi Osaka fights back from set down against Victoria Azarenka to claim third Grand Slam title
The win brought 22-year-old Osaka's haul of tennis major trophies to three after her victories at the 2018 US Open and 2019 Australian Open.
US Open 2020, Women's final highlights: Naomi Osaka beats Victoria Azarenka for her third Grand Slam title
Follow live score, updates and reactions from the US Open 2020 women's final between Naomi Osaka and Victoria Azarenka in New York.
US Open 2020: Naomi Osaka, Victoria Azarenka seek third Grand Slam title, look to continue unbeaten run
On court, both Naomi Osaka and Victoria Azarenka have been breathtaking at the US Open. Off the court, both have taken different paths on social issues.
US Open 2020: Victoria Azarenka pulls off come-from-behind win over Serena Williams to set up final with Naomi Osaka
The unseeded Belarusian fought back to overcome Williams, seeded third, 1-6, 6-3, 6-3 in 1hr 56min under the roof of Arthur Ashe Stadium.
US Open 2020, Women's semi-finals, Match Highlights: Victoria Azarenka beats Serena Williams in comeback win
Follow US Open live scores and coverage as the action moves to the women's singles semi-finals on Day 11.
US Open 2020: Carreno Busta downs Shapovalov in five sets to reach semi-finals; Osaka races past Rogers
Alexander Zverev also reached the last 4 of the US Open as he bounced back from a shocking start to oust 27th-seeded Croatian Borna Coric in four sets.
US Open 2020: Naomi Osaka beats Shelby Rogers in straight sets to set up semi-finals clash with Jennifer Brady
The Japanese 2018 US Open champion brushed aside the 27-year-old American 6-3, 6-4, in 1hr 20min inside Arthur Ashe Stadium.
US Open 2020, Quarter-finals, Tennis Highlights: Pablo Carreno Busta to face Alexander Zverev in last-four; Naomi Osaka vs Jennifer Brady in semis
Follow all the latest action, live scores and more from the US Open 2020 quarter-finals on Firstpost.com's live blog!
Naomi Osaka, who won the US Open two years ago, advanced to the quarterfinals by beating No. 14 seed Anett Kontaveit 6-3, 6-4.
US Open 2020: Borna Coric stages epic comeback to stun Stefanos Tsitsipas; Novak Djokovic sails into last 16
Croatia's 27th seed Borna Coric staged a remarkable Houdini act to stun fourth seed Stefanos Tsitsipas in a 4hr 36min late-night thriller.
US Open 2020: Novak Djokovic opts for $40,000 home over hotel; virtual applause for Naomi Osaka from Mom
Serena Williams and Milos Raonic were among the eight players who, like Djokovic, opted for one of the Long Island homes the USTA made available.