Simmons, the first overall pick of the 2016 NBA Draft, suffered a Jones fracture in his right foot during training camp. He underwent surgery on Sept. 30 and was supposed to return in three months.
However, the latest tests have revealed that an inside portion of the broken bone in his foot is not completely healed, sources told Keith Pompey of Philly.com.
Simmons has progressed to the stage of conducting on-court drills, but Pompey relays that the team has kept him out of scrimmages for fear of causing further damage.
Foot injuries, Jones fractures in particular, are tricky by nature. Kevin Durant is a recent reminder that the healing process isn't necessarily linear. Cameron Payne has also bounced in and out of the lineup since breaking his foot.
Injuries have undercut each of the Sixers' promising young talents. Joel Embiid missed two seasons with a broken foot, and is now sidelined with a knee injury, while Nerlens Noel sat out a year on account of a torn ACL. Jahlil Okafor also missed a handful of games in his rookie year.