The Nets said Sunday that Lopez would miss their game Monday against Cleveland and that he would be re-evaluated in a week.
Lopez had played well in recent games after struggling earlier this season in his return from surgery to repair a broken foot. He scored 20 points Friday against Atlanta and had 16 points and 16 rebounds two nights earlier in a victory over San Antonio.
He is averaging 16.1 points and 6.2 rebounds.
The Nets also said guard Joe Johnson was listed as probable for the game after missing practice Sunday with a stomach virus.