Video surfaced Monday on social media that showed a maskless Irving at an indoor party. The league said the event occurred last weekend.
"Brooklyn Nets guard Kyrie Irving has been fined $50,000 for violating the league's health and safety protocols, which among other things prohibit attending indoor social gatherings of 15 or more people or entering bars, lounges, clubs or similar establishments," NBA president of league operations Byron Spruell said in a news release.
The league said Irving can return to the team Saturday, which means he missed his two previous games due to his five-day quarantine. Irving had to forfeit his salary for those games. His total financial penalty due to the NBA disciplinary measure is expected to exceed $850,000.
Irving hasn't played since Jan. 5 because of what the team called "personal reasons." He missed five-consecutive games.
The Nets will host the Orlando Magic at 6 p.m. EST Saturday at Barclays Center in Brooklyn, N.Y. Irving can only return for the game if he continues to test negative for COVID-19.
James Harden -- who joined the Nets through a trade Thursday -- is expected to make his debut with the team then. Harden was fined $50,000 earlier this season for violations of the league's COVID-19 protocol.