Sixers president Ed Stefanski said there was no contact when Smith was hurt Wednesday.
"It's unfortunate that this happened, but Jason is resilient and he'll receive the best treatment available," Stefanski said Friday.
Smith, a second-year player out of Colorado State, averaged 4.5 points and 3.5 rebounds as a rookie. He averaged 18.6 points and 8.0 rebounds in five games in the Las Vegas summer league.
A team doctor examined Smith on Thursday, and he'll get a second opinion in the upcoming weeks. It's unclear when he'll be able to return to the court.