Williams has had ongoing knee issues since missing his junior season of high school due to a joint condition in his right knee. He missed multiple games in January and February of last season with soreness in the knee. His latest issue has been a concern for a few months, as Williams was dealing with side effects from a previous surgery, sources told ESPN.
"I want to thank my family, fans and the Arizona Basketball program for their continued support," Williams said in a statement. "I've overcome obstacles before in my life and will work with our strength and medical staffs to overcome this one. I'm dedicated to continuing my work in the classroom as a student, and I look forward to supporting my teammates and coaches as I spend this season focusing on my health."
Williams, a former ESPN 100 recruit, started 21 games as a freshman for Arizona. He averaged 11.4 points and 3.4 assists.
"Brandon is one of the most talented guards we have recruited during my tenure as head coach at Arizona," coach Sean Miller said. "A year ago, Brandon quickly became one of our team's best players and one of the Pac-12's most exciting freshmen. The news of Brandon's season-ending surgery is beyond disheartening. All of us that comprise Brandon's Arizona Basketball family, as well as our own loyal and passionate fan base, will rally around him and support him as he begins his journey to recovery."
The Los Angeles native was expected to play a key role in the backcourt during the 2019-20 season, alongside top-10 incoming freshmen Nico Mannion and Josh Green. Without Williams, expect UC Irvine graduate transfer Max Hazzard to play a bigger role. Returnees Dylan Smith and Devonaire Doutrive will also see consistent time on the perimeter.
Arizona was ranked No. 16 in ESPN's Way-Too-Early Top 25.