While there's no timeline for a Simmons return, an evaluation in two weeks is more of an initial benchmark date than an expectation of a quick return to the lineup, sources said.
Doctors are hopeful treatment can drive improvement, but the Sixers are preparing to play without him, sources said.
Simmons played less than five minutes in Philadelphia's loss to the Bucks on Saturday night before exiting with back soreness. He also missed Thursday's overtime win at home versus the Brooklyn Nets with lower back tightness and Monday night's game against Atlanta.
Simmons is averaging 16.9 points, 7.9 rebounds and 8.3 assists this season.
-- ESPN contributed to this report.