Russell was injured in Saturday's loss to the Mavericks. He also is battling a virus that has affected multiple members of the team.
"Not sure how long he'll be out," Golden State coach Steve Kerr said. "He had a little neck pain when he woke up [Sunday]."
Center Willie Cauley-Stein also is dealing with illness and didn't play.
Backup big man Kevon Looney also missed Tuesday's game because of abdominal soreness.