"He's feeling better but not well enough to play," Heat coach Erik Spoelstra said before the game.
Wade, who leads the Heat with 19.2 points per game, was injured on a hard fall during Wednesday's loss to the Lakers. He watched Miami's 112-106 victory over Sacramento on Friday from the bench in street clothes.
"It got worse [Friday]," Wade told reporters after Friday's game. "The impact I made when I hit the floor, my lower back is real sore. And my neck, from my head hitting the floor, is real sore. It's hard to walk normal, and it's hard to look left or right fast. ...
"There's nothing I can do except take it one step at a time because it's not just my back. It's my back and my neck. [They're] equally bad. When I feel like I can move around, do things I need to do, I will jump back out there."
Spoelstra, who said Wade was walking like Frankenstein, said there is no timetable for Wade's return.
Gerald Green started in place of Wade and scored a season-high 30 points.
Despite the loss, the Heat still clinched a playoff spot after the Chicago Bulls fell 94-90 to Detroit earlier in the evening. Miami came into the game tied for the third seed in the East but dropped to sixth with the loss.
The Associated Press contributed to this report.