Williams and Lopez are both dealing with ankle injuries.
The team will also be without forward Andrei Kirilenko and guard Jason Terry. Kirilenko has a back injury and Terry is dealing with a bruised left knee.
The Nets are 3-8 this season and have lost three games in a row.
Williams injured his left ankle during the second quarter of Wednesday night's 95-91 loss to the Charlotte Bobcats when he landed on Bobcats guard Kemba Walker's foot after shooting a jumper. Lopez, who leads the team in scoring and blocked shots, will miss his fourth straight game.