Meanwhile, rookie guard Josh Giddey, who leads the Thunder in rebounds and assists, is off the team's COVID-19 list after entering the protocols Tuesday.
Gilgeous-Alexander is averaging a team-leading 22.7 points to go along with 4.8 rebounds and 5.2 assists.
Oklahoma City has six players out with COVID-19 issues -- Gilgeous-Alexander, Darius Bazley, Derrick Favors, Tre Mann, Aleksej Pokusevski and Jeremiah Robinson-Earl -- along with coach Mark Daigneault.
The Thunder (13-22) host the Dallas Mavericks (17-18) on Sunday.
The NBA has changed its protocols at least twice in recent days after data suggested it could safely shorten the return-to-play plans for those who test positive for the virus, provided that the players are asymptomatic and return multiple test results that meet the league's standards for showing they are no longer contagious.
By late Saturday afternoon, the number of players revealed by teams to be in the protocols was around 100, about a 20% dip from the highest known figure the NBA was dealing with earlier in the week. The numbers fluctuate on almost an hourly basis; some players are closer to a return than others.
The Associated Press contributed to this report.