Williams landed hard on his right wrist multiple times in Tuesday's 93-76 loss to the Boston Celtics. He had revealed to reporters in late November he was playing through a sprained right wrist, among other minor injuries.
Still, Williams had started each of the team's first 27 games prior to Wednesday.
"It's been kind of flaring up throughout the season," Nets coach Avery Johnson told reporters in Milwaukee. "It seems like every time he falls, he falls directly on it."
Johnson added that Williams will be evaluated on a "day-in and day-out basis" before determining if he can return for Friday night's home game against the Bobcats.
Williams, 28, is having one of the worst seasons of his career. He's shooting a career-low 39.8 percent from the field and 29.5 percent from 3-point range. He's averaging just 16.6 points per game, his lowest output since 2006-07, his second season in the NBA.
His 8.0 assists per game is his lowest output since his 2005-06, his rookie year.
The Nets were also without power forward Kris Humphries, who missed his second straight game because of a strained abdominal muscle.
Backup point guard C.J. Watson started for Williams.
Mike Mazzeo is a regular contributor to ESPNNewYork.com.