Lopez suffered the injury Wednesday against the Atlanta Hawks. Nets coach Kenny Atkinson said Lopez injured the ankle early in that game but kept playing.
Atkinson said he thought Lopez's injury was "a tweak" and that he expected his leading scorer to return soon.
Quincy Acy, a former Baylor standout who began the season with the Mavericks, started in Lopez's place against his former team Friday. He scored 12 points and grabbed four rebounds in 23 minutes.
Lopez, a ninth-year player, has started all 58 games in which he has appeared, averaging 20.3 points and a team-best 1.8 blocks. He also averages 5.1 rebounds.