Montgomery (knee) is reportedly nursing a sprain that is expected to sideline him 4-5 weeks, Dan Graziano of ESPN.com reports.
The Bears aren't expected to provide an official update on Montgomery's status until Wednesday, but early test results at least suggest he's avoided a season-ending issue. If a recovery timetable between four and five weeks is indeed accurate, Montgomery will likely end up seeing a stint on IR. Damien Williams appears the favorite to lead Chicago's backfield in the meantime, assuming he can manage to play through a thigh bruise. The Bears also have rookie Khalil Herbert around to pick up some slack, with a road matchup against the Raiders on deck for Week 5.