According to Bob Cooney of the Philadelphia Daily News, Sixers general manager Bryan Colangelo said Simmons will not play this season since a scan did not show full healing in his foot.
Brian Windhorst of ESPN added Simmons also won't participate in Summer League, per Jake Pavorsky of Liberty Ballers.
Simmons underwent surgery to repair a broken bone in his right foot in October.
ESPN's Jeff Goodman (h/t ESPN.com's Marc Stein) reported prior to the surgery that Simmons was expected to miss three months with a return date in December or January.
The Sixers have struggled through misfortune in recent years with regard to their early first-round draft picks.
Big man Joel Embiid missed each of his first two NBA seasons with a foot ailment and continues to deal with injuries during the current campaign as well.
Philadelphia drafted the 20-year-old Simmons first overall after a single season at LSU that saw him average 19.2 points, 11.8 rebounds, 4.8 assists and 2.0 steals per game.
While Philly is just 21-35 this season, it has made progress with 11 more victories than it had in all of 2015-16.
With a young core that includes Embiid, center Jahlil Okafor and forward Dario Saric, the arrival of Simmons in 2017-18 if healthy may be the factor that finally pushes the Sixers back into playoff contention.