On the second day of the new NBA season, a game has been postponed due to Covid-19 – and a league star got hit with a fine for violating protocol.

The NBA announced Wednesday that the game between the Oklahoma City Thunder and the Houston Rockets at the Toyota Center in Houston has been postponed in accordance with the league's health and safety protocols.

Additionally, the league said Rockets star James Harden was unavailable to play in the game against the Thunder due to a violation of the health and safety protocols.

The league subsequently announced Wednesday that Harden has been fined $50,000, saying the Rockets guard violated rules when he attended a private indoor party on Monday.

NBA rules currently prohibit attending indoor social gatherings of 15 or more people or entering bars, lounges, clubs or similar establishments. The NBA said three Rockets players have returned tests that were either positive or inconclusive for Covid-19 under the NBA's testing program. Four other players are quarantined at this time following contact tracing.

The league said that all other Rockets players were tested again Wednesday, and all returned negative results. Houston has one additional player who is unavailable due to an injury.

Because of all of this, the Rockets do not have the league-required eight available players to proceed with Wednesday night's game against the Thunder, the NBA said. This isn't the first time the Thunder have had a game impacted by Covid-19.

On March 11, the NBA halted the 2019-2020 season after Rudy Gobert of the Utah Jazz tested positive for Covid-19 ahead of the team's game against the Thunder in Oklahoma City.

The season resumed in late July with playoff-contending teams at the Walt Disney World Resort just outside of Orlando, Florida, and ended on October 11 with the Los Angeles Lakers winning the NBA Finals.

The league is not using a bubble this season, instead playing in teams' home arenas with the exception of the Toronto Raptors. The Raptors are playing home games in Tampa, Florida.