Montgomery (shoulder) was listed as a non-participant in Monday's walkthrough, Tim Twentyman of the Lions' official site reports.
Montgomery injured his shoulder in Sunday's win over the Colts and wasn't cleared to return in the second half. Despite the early exit, Montgomery said after the Week 12 victory that he anticipated being ready for Thursday's game against the Bears. Montgomery likely will need to practice in some fashion Tuesday or Wednesday in order to play on the short week. If Montgomery is unable to go, Jahmyr Gibbs would be a candidate for increased work out of the backfield.