Booker appeared to suffer an injury with 4:30 left in the third quarter after challenging a Jaxson Hayes dunk in transition. He grabbed at his leg and asked teammate Chris Paul to call a timeout before going to the locker room.
Suns coach Monty Williams confirmed the issue and said the team would learn more after the game during an interview with TNT before the start of the fourth quarter.
The team later called it right hamstring tightness and said Booker would not return.
Booker missed seven games in December with a left hamstring strain and had issues with it last season as well.
He made 12 of 18 shots and hit seven 3-pointers in an electric first half Tuesday that got the Suns, who are up 1-0 in the series, the lead. But he took only one shot, a miss, and didn’t score in the third quarter before leaving.