There is no timetable for Smith's return.
The injury is all too familiar to the Sixers, who saw Ben Simmons' 2016-17 campaign end before it started after he suffered an acute Jones fracture during training camp.
On the bright side, Simmons returned at full strength last season and romped his way to Rookie of the Year honors while appearing in 81 of 82 games for the Eastern Conference's No. 3 seed.
Smith, whom the Sixers acquired in a draft-night trade with the Phoenix Suns, was expected to assume a modest workload as a rookie. As a result, his absence shouldn't alter head coach Brett Brown's rotation all that much.
Simmons, Markelle Fultz, JJ Redick and TJ McConnell should remain penciled in as the Sixers' top four guards moving forward.