The Lakers announced the deal Monday.
The 7-foot Upshaw led the nation with 4.5 blocked shots per game until his dismissal from the University of Washington's team last season. He went undrafted after leaving school two years early.
The native of Fresno, California, was kicked off the team at Fresno State and Washington for violations of team rules during his two-season college career.
Upshaw got the Lakers' attention while playing five games for their summer league team.
The Lakers have 18 players on their roster heading into training camp in Hawaii later this month. Los Angeles is coming off the worst season in franchise history at 21-61.