The league announced that decision on Wednesday afternoon, just hours before tip-off.
The issue was with the Rockets, who did not have the minimum eight available players for the game.
According to a statement from the NBA, three Houston players returned test results that were either positive or inconclusive. As a result, four additional Rockets were placed in quarantine for contact tracing reasons.
Additionally, Rockets star James Harden was declared unavailable for the game after violating the league’s COVID-19 policies, the release said.
The Rockets also have one player out due to injury, bringing them below the eight-player minimum.
It’s unclear when or if this game will be made up.
This is a bit of a full circle moment for the Thunder, who were also in the spotlight for a cancelation back on March 11 when Jazz center Rudy Gobert tested positive just minutes before tip off.
The 2020-21 NBA season began on Tuesday night, with the Brooklyn Nets and Los Angeles Clippers securing victories over the Golden State Warriors and Los Angeles Lakers, respectively.
OKC’s season-opener will now take place on Saturday against the Charlotte Hornets.