James Wiseman will undergo surgery to repair a meniscus injury in his right knee on Thursday.
Steve Kerr said that a timetable couldn't be determined until afterwards.
Kerr added that the team spoke to several medical experts before deciding on surgery.
"He's a young guy -- this isn't supposed to happen so early in someone's career. So it's a tough time for sure. So fingers are crossed, and we'll see how everything goes [Thursday]," said Kerr.