Allgeier is listed as active Sunday at the Rams, Tori McElhaney of the Falcons' official site reports.
A rookie fifth-round pick, Allgeier was a healthy scratch during the Falcons' season-opening loss to the Saints, as the team rolled with Cordarrelle Patterson, Damien Williams and Avery Williams at running back. Damien Williams picked up a rib injury during that contest and proceeded to miss every Week 2 practice before the team ruled him out Friday and placed him on IR on Saturday. With the older Williams sidelined for at least the next four games, Allgeier will get a chance to make his presence felt on the field, though Patterson still is expected to garner most of the RB reps Sunday.