Sean Wright is the game's third referee.
Sago has been a full-time NBA official since 2018, and Schroeder became the league's fourth full-time female referee in 2019.
Lauren Holtkamp-Sterling, Ashley Moyer-Gleich and Simone Jelks are the other three women who currently serve as referees. There have been seven female full-time referees in NBA history.
"It's an area, frankly, where I've acknowledged that I'm not sure how it was that it remained so male-dominated for so long," NBA Commissioner Adam Silver said in 2019. "Because it's an area of the game where physically, certainly, there's no benefit to being a man, as opposed to a woman, when it comes to refereeing."
The NBA has become increasingly committed to diverse hiring practices under Silver. The Institute for Diversity and Ethics in Sport (TIDES) at the University of Central Florida gave the league an A-minus score in 2020. Women comprise about one-third of NBA team management positions.