"He's being evaluated [Saturday]. We haven't gotten the results back yet," interim head coach Luke Walton told reporters before Saturday's game. "It's all speculation. It could be a few weeks. It could be a week.
"We're not going to rush him back because we want to be healthy for later in the season and we don't want lingering injures, so we'll have him take his time."
With just more than nine minutes left in the third quarter, Barnes was defending Suns forward Markieff Morris when he landed on Morris' foot. The ensuing fall caused Barnes to grab below his knee. He was helped to the locker room by trainers and teammates.
The Warriors announced his injury shortly after and said he would not return. X-rays were negative, the team said.
Barnes entered the contest averaging 13.8 points, 4.9 rebounds and 2.1 assists per game for the Warriors.
He had seven points, seven rebounds and no assists in 21 minutes as they moved to 17-0.
The Associated Press contributed to this report.