The NBA currently has 10 referees sidelined due to issues related to COVID-19 and, in one case, an injury.
The league has had 24 referees miss at least one game this year due to health and safety protocols.
Most of the absences have been tied to contact tracing.
While teams travel via charter flight, referees fly commercially, exposing them to more individuals who could be carrying COVID-19.
Teams have said the quality of the officiating have negatively impacted games.
"It's been bad all year," one GM told ESPN.
Said a second GM about the replacement officials: "Young and inexperienced."
When asked if the lower-tier officials have impacted the quality of officiating, a third NBA GM said: "That's an understatement."