In the aftermath of his violating coronavirus protocols and absorbing a $50,000 fine, the NBA is mandating that Houston Rockets All-Star James Harden quarantine and test negative for four days, which should clear the way for his return Saturday against the Portland Trail Blazers, sources told ESPN.

The league's medical staff started the clock on a Harden quarantine with Tuesday's negative test and he should receive clearance on Friday, sources said.

Harden was disciplined after video surfaced of him at an indoor gathering in Houston without a mask. He wouldn't have been allowed to play in the Rockets' scheduled game against Oklahoma City on Wednesday, which was eventually postponed because Houston couldn't meet league guidelines with eight eligible players.

The video of Harden partying maskless, which was published by Black Sports Online and has been circulating on social media, is purportedly from a Houston club's Christmas party held this week.

The NBA's COVID-19 protocols prohibit players from going to bars, lounges or clubs and from participating in social gatherings of more than 15 people.

The league said Harden violated those rules when he attended a "private indoor party" on Monday.

Harden has told NBA investigators he believed he was in compliance with health and safety protocols, a source close to the situation told ESPN's Ramona Shelburne. Harden and multiple witnesses at the event have told the league that he attended a seated dinner for a friend who had recently been promoted at work, the source said.

According to the source, Harden said he entered through a separate entrance, sat in a separate area of the venue with his security detail and was wearing a mask. He took a photo with his friend and gave her a gift. Harden, according to the source, said he left after approximately 30 minutes and did not continue on with the group, which went to other locations later in the night.

Harden, who has requested to be traded, violated the NBA's COVID-19 protocols during his brief holdout at the beginning of training camp when he attended rapper Lil Baby's birthday party in Atlanta and frequented Las Vegas clubs. The league required Harden to have six consecutive days of negative coronavirus tests before clearing him to practice with the Rockets.

Sources told ESPN that Harden had COVID-19 during the summer before the NBA season restart, which is why he was late reporting to the league's Walt Disney World bubble. Players who have recovered from the coronavirus are still required to follow the league's health and safety protocols.

ESPN's Tim MacMahon contributed to this report.