Williams, who came off the bench the last six games after returning from ankle injuries, will start alongside Shaun Livingston, Joe Johnson, Paul Pierce and Kevin Garnett in Saturday night's game against the Indiana Pacers.
Alan Anderson, who had been starting, will come of the bench.
The Nets were without Andrei Kirilenko (sore right calf) and Andray Blatche (bruised left hip) on Saturday night. Kirilenko will be missing his second straight game. Blatche suffered his injury in the first half of Friday night's 120-95 loss to the Oklahoma City Thunder.
It is unknown how long both players will be out.
Williams, who had missed five games after getting a cortisone shot and a PRP injection in both of his ankles, decided that he'd play a reserve role when he came back because he didn't want to mess up the chemistry that starters Livingston, Anderson, Johnson, Pierce and Garnett had developed. But the Nets (20-24) have lost two straight games, and struggled to get off to good starts, prompting coach Jason Kidd to make a change.
During his six-game bench stint, Williams averaged 11.7 points and 7.0 assists on 45.5 percent shooting in 30.8 minutes.