The 26-year-old American has not played competitively since being forced to retire from her second-round match against Jelena Ostapenko at Cincinnati in August.
The list of players heading to Japan includes 17-year-old Gauff, 2021 Australian Open runner-up Brady, Jessica Pegula and Alison Riske for women's singles, and Tommy Paul, Frances Tiafoe, Tennys Sandgren and Marcos Giron for men's singles.
Djokovic, bidding to be the first man in more than half a century to win all four majors on multiple occasions, can reach the last 16 for a 12th consecutive year with victory over the sea-loving Lithuanian.
You have to go back to 1996 to find this many US men in the third round; a half-dozen got there then.
A leg injury meant Osaka missed last season's clay-court swing, and her last individual tournament on the surface was at Roland Garros in 2019.
The Australian rallied from losing the first set to claim a 3-6, 6-0, 6-3 win over Sabalenka, who needed a medical time-out after the second set for an adductor injury.
Naomi Osaka withdraws from Stuttgart Open, to begin clay court season 'a little later,' say organisers
"Naomi Osaka will now begin the European clay court season a little later in May," said the Stuttgart organisers in a statement.
Despite conceding the first set, Russia's Kuznetsova put up a spirited defence in the second leading to increasingly sprawling rallies with her well-matched Belarusian opponent.
Naomi Osaka has four Grand Slam titles, and remains unbeaten in major finals after lifting the 2021 Australian Open. But more remarkably, each of her Slam has been significant to her as a player and a person.
23-year-old Naomi Osaka won her fourth Slam from the last eight she's contested. She became only the third player after Monica Seles and Roger Federer to win their first four major finals
Osaka's triumph over Jennifer Brady in the Australian Open final was hailed in Japan, and beyond, as astronaut Soichi Noguchi wrote from space "Naomi Osaka, congratulations on the victory," with a gold-medal emoji.
Australian Open 2021: Jennifer Brady says winning a Slam no longer feels as improbable as 'going to Mars'
Brady reached the Melbourne final despite undergoing 14 days' hard quarantine in Australia, forced to stay in her room while other players were allowed out every day to train.
The 23-year-old's zen-like mentality and increased gravitas on and off the court have elevated her alongside Serena Williams to being the one of the most recognisable female athletes on the planet.
"I'm probably going to watch some anime... maybe (eat) pizza... and go to sleep," said Osaka after winning her fourth Grand Slam title.
Naomi Osaka clinched her fourth Grand Slam title on Saturday after beating Jennifer Brady at the Australian Open. Here's how her two US Opens and two Australian Opens were won:
Naomi Osaka registered multiple records and milestones following her Australian Open title win on Saturday against Jennifer Brady.
Osaka edged a tight first set but controlled the second to win 6-4, 6-3 in 77 minutes in front of thousands of fans at Rod Laver Arena.
Australian Open 2021 Women's final: Japan's Naomi Osaka maintained her perfect record in Grand Slam deciders by beating Jennifer Brady 6-4, 6-3 to win her fourth major title.
Australian Open 2021: Naomi Osaka will put her winning streak, Slam record on line against big-hitting Jennifer Brady
Naomi Osaka goes for her fourth Grand Slam title in the Australian Open final on Saturday. Standing in her path is Jennifer Brady - playing her maiden final.
Australian Open 2021: Naomi Osaka halts Serena Williams' bid for 24th Slam title; Novak Djokovic marches on
Fans witnessed an emotional exit from Williams, Jennifer Brady's win over Karolina Muchova and top-ranked Djokovic preserving his perfect semi-final record at Karatsev's expense.