(AP) – The NBA and its players have agreed to enhanced health and safety protocols through the holiday season in response to rising virus numbers, with additional testing coming and a return to mask usage in many situations.

The upgraded mask rules will be in place “until agreed otherwise by the NBA and Players Association,” according to a memo shared with teams Thursday night and obtained by The Associated Press. Masks need to be worn again in almost all circumstances during team activities — including travel, when on the bench during games, in meetings and locker room, weight room and training room settings.

The exceptions: during on-court basketball activities for players, and for head coaches during games.

Testing will be increased from Dec. 26 through Jan. 8, the league said. The league also told teams that more requirements and recommendations would be coming in the next few days, “to help reduce the risk of COVID-19 spread within the team environment.”

The memo was released on the same day that Russell Westbrook entered the health and safety protocols, joining Milwaukee’s Giannis Antetokounmpo and Brooklyn’s James Harden as past league MVPs currently sidelined by coronavirus concerns.

Westbrook played 42 minutes for the Los Angeles Lakers on Wednesday night in their overtime win at Dallas. The Lakers said he would not play Friday night in Minnesota, along with four other players because of virus issues and two more because of injuries. ESPN, however, reported that one of the five Lakers in the protocols — Malik Monk — tested out Thursday night, which would make him eligible to play Friday.

If granted permission by the NBA to sign reinforcements and temporarily exceed the roster-size limit, the Lakers were planning to sign former All-Star guard Isaiah Thomas to a 10-day hardship contract Friday, according to a person with direct knowledge of the negotiations. The person spoke to The Associated Press on condition of anonymity because of the pending league approval.

As of Thursday evening, there were at least 39 players — roughly 8% of the league’s total player roster — from at least 13 different teams known to be in the league’s protocols. Chicago had a league-high eight players known to be in protocols, one more than Brooklyn. Harden and Antetokounmpo both entered the protocols earlier this week.

Washington coach Wes Unseld Jr., speaking to reporters in Phoenix before the Wizards’ game there Thursday, said the rise in numbers — in the NBA, other leagues and around the country — is “a huge concern.”

“Protocols are put in place,” Unseld said. “We’ve been testing for some time now with the cases that we’ve had. It’s not unusual. It’s not unique to our team. Obviously, look around the landscape of the league and this country; there’s been a dramatic uptick in cases. Knock on wood, the severity of those cases and the rate of hospitalizations don’t appear to be as dramatic. But it’s still very real.”

Thomas scored 42 points for Grand Rapids in a G League game Wednesday night and recently appeared in two games for USA Basketball in World Cup qualifying games in Mexico. He was in the NBA briefly last season, averaging 7.7 points in three games with New Orleans.

If it happens, it’ll be his second stint with the Lakers. He appeared in 17 games with them during the 2017-18 season.

“For me, personally, the ultimate goal is to get back in the NBA,” Thomas, who averaged 29 points for the Boston Celtics in 2016-17 and spent a considerable amount of time battling injuries since, said last month. “But I just love playing the game of basketball. … I love competing and I love playing against the best players in the world.”

There was a bit of good news Thursday when the Bulls revealed that two of their 10 players who entered protocols have since been cleared for a return.

The Bulls had two games this week postponed because of a player shortage. For now, they’re scheduled to return to play Sunday at home against the Lakers.

“We got hit really hard with all this and we lost a lot of players,” Bulls coach Billy Donovan said Thursday. “Other teams have maybe been hit a little bit, but not as much.”

The NBA was up to 430 games played as of Thursday, or 35% of the season. The two Bulls games this week are the only ones postponed by virus concerns.