Hollis-Jefferson became an unrestricted free agent after the Brooklyn Nets declined to make a qualifying offer to him in order to maximize their cap space.
The 24-year-old, who joined Brooklyn in a trade after being selected 23rd overall in the 2015 NBA Draft, had developed into one of the team's most versatile defenders.
Hollis-Jefferson averaged 8.9 points and 5.3 boards across 59 appearances last season.
Both players were teammates at Arizona during the 2014-15 collegiate season and led the school to an Elite Eight appearance.
Hollis-Jefferson made the All-Pac-12 first team and earned Pac-12 All-Defensive team honors that year.