The team announced that the ankle injury will keep Williams out for the rest of the weekend, and he will be reevaluated on Monday.
Williams has missed six of the last seven games with multiple left ankle sprains.
Nets center Brook Lopez, who has missed the previous seven games with an ankle injury of his own, is listed as as a game-time decision tonight, and he hopes to play.
Update: The Nets have announced that Lopez will play tonight.
Backup center Andray Blatche, who also sprained an ankle Wednesday night, was not listed on the injury report and will play tonight.
Andrei Kirilenko (back) and Jason Terry (knee) also did not make the trip to Houston, and the Nets say they will both be out at least another week.
The Rockets will be without point guard Jeremy Lin tonight. Shooting guard James Harden is a game-time decision with a left foot injury.