Montgomery (thigh) remained sidelined during Thursday's practice, Kyle Meinke of MLive.com reports.
Montgomery also missed Wednesday's session, which sets the stage for Friday's practice to loom large for the running back in terms of his chances of suiting up Sunday versus the Falcons. If Montgomery is unavailable this weekend, Jahmyr Gibbs would be in a position to see added touches Week 3, with Craig Reynolds and Zonovan Knight on hand to serve as complementary options in Detroit's backfield.