As the omicron variant rips through NBA players and coaches, it has reached a season-high among game officials: 36% of the league's referees are in COVID-19 protocols, sources told ESPN on Thursday.

With 25 of the league's 70 active referees currently in quarantine, the league has been promoting G League referees to fill out the nightly roster of games, sources said.

There have been rare instances lately when only two referees -- instead of the standard three -- were available for games, but the NBA has continued to work to limit those occasions, sources said.

The G League has paused the season until Wednesday to allow for players and referees to be available to the NBA.

NBA referees are 100% vaccinated and are required to be fully boosted prior to Wednesday, sources said. Only a percentage of refs currently on road trips haven't been boosted, but must do by Wednesday.

Officials don't have the protections that teams do with charter flights and five-star hotels, but the NBA has been working with the National Basketball Referees Association on improvements related to travel -- including hotels -- that might serve to lessen exposure to the virus, sources said.