Malcolm Brogdon left the Indiana Pacers' 111-102 loss to the Houston Rockets in the first quarter with a sore lower back.
Brogdon did not return to the game.
"That's a big loss when you're going up against guys like Harden and Westbrook. Not only do you need him offensively but you need his size defensively," said Nate McMillan after the game.
Brogdon is averaging 20.7 points and 8.5 assists on the season.