Embiid had been listed as questionable for the game with soreness in his left knee, which forced him to miss Philadelphia's practice on Saturday.
"It's not anything that we're concerned about," Brown said. "We're just reacting to his thoughts and the medical staff's thoughts that tonight might be a good place to sit.
"It's something that is recent and (we're) just being precautionary with it."
After missing his first two seasons in the NBA due to a navicular fracture in his right foot, 51 games in 2016-17 (when he underwent surgery on a meniscus tear in his left knee) and 19 games last year, Embiid had played in 35 of the 76ers' first 36 games this season.
The only game Embiid had missed in 2018-19 was for rest rather than a specific injury. Embiid's averages of 26.5 points, 13.3 rebounds and 1.9 blocks lead the Sixers, who were 23-13 entering Sunday's game.
Brown told reporters that veteran Amir Johnson will start in place of Embiid.