The Nets also were without small forward Gerald Wallace, who missed his third straight game because of a sprained left ankle.
Brooks suffered the injury when he stepped on reserve center Andray Blatche's foot during a pick-and-roll coverage drill.
Nets coach Avery Johnson called it "a freak accident."
"I tried to walk it off, but it really wasn’t feeling the way I wanted, so I’m just gonna sit out," Brooks told reporters in a video posted on the team's official website. "It’s kind of frustrating because I'm finally playing well, getting some shots to fall and then this happens."
Brooks, 23, is averaging 10.3 points, 2.3 rebounds and 1.3 assists per game for the Nets (1-2).
Wallace, 30, scored 10 points, grabbed six rebounds and dished out four assists in Saturday night's season-opening victory over the Toronto Raptors before getting injured in the final minute.