"We wish Rob well as he moves forward in his life, and we will do our best to support him in the future," Washington coach Lorenzo Romar said in a statement.
Upshaw, who transferred to UW from Fresno State, has failed multiple drug tests while at both schools, sources close to the situation told ESPN.
The ultra-talented big man averaged 10.9 points, 8.2 rebounds and 4.4 blocks per game for the Huskies and leads the nation in blocks.
Washington is coming off a loss at Utah on Sunday in which Upshaw scored 13 points, grabbed nine rebounds and blocked five shots. The Huskies (14-5, 3-4 Pac-12) will host Stanford on Wednesday.