Smart clutched at his lower left leg after getting his arm hooked by Indiana's A.J. Price and crashing to the floor with 11:07 left in the fourth quarter Friday night.
Smart never got up and his teammates gathered around as medical personnel attended to his injury. Boston fans chanted Smart's name and gave the guard a standing ovation as he was carted off on a gurney with his left leg elevated.
Boston selected Smart out of Oklahoma State with the sixth choice in this year's NBA draft. The next pick was Los Angeles Lakers forward Julius Randle, out for the season after breaking his right leg on opening night.