The 33-year-old striker announced his "U-turn" 11 days after informing the club that he wanted to leave this summer and arguing that a clause in his contract meant he could leave for free.
It is the second such injury in eight months for Zaniolo, as the 21-year-old was stretchered off in the Serie A game between Roma and Juventus in January, following a tackle with Adrien Rabiot and Matthijs de Ligt.
It was Atletico's fourth win from six matches this campaign and lifted Jorge Sampaoli's side to third in the 20-team standings, four points behind leaders Internacional.
In a statement, Fluminense did not disclose details of the move nor the name of the 20-year-old's new club, though widespread media reports in Brazil and Portugal said he had signed with Porto.
Keeper Han Jiaqi made key saves to keep the three points for R&F, with Jianye unable to score in the second half.
Then in the third set, Williams was rarely troubled by her rival en route to the victory.
Slovenia's Roglic arrived with the leading group to remain 21 seconds ahead of defending champion Egan Bernal on the overall standings.
The Kenyan was the third pacemaker on Sept. 4 at Brussels Diamond League in the One Hour race which saw Dutchwoman Sudan Hassan, the reigning world 1,500 and 10,000m champion, produced a thrilling kick over the final minute to see off Kenyan world marathon record holder Brigid Kosgei and notch up an astonishing 18.930km over the 60 minutes.
The other match on Friday saw Shenzhen Jiazhaoye held Shanghai Shenhua to a 0-0 draw.
Ghanaian President Nana Addo Dankwa Akufo-Addo has given special dispensation to the country's male and female under 17 and under 20 teams to resume their respective camps to prepare for major international assignments.
The German coach announced he is taking the clubs' challenges into account but, at the same time, will stick to the national team's rejuvenation process, including having to re-structure his defense.