The Bears also elevated RB Ryan Nall to their active roster for Sunday’s game.
Montgomery is dealing with a sprained knee that was expected to sideline him for the next four or five weeks, so this move was expected.
The Bears can activate him from injured reserve after he misses the next three games.
Montgomery, 24, was drafted by the Bears in the third round out of Iowa State in 2019. He is currently in the third year of his four-year rookie contract worth $4.015 million.
In 2021, Montgomery has appeared four games for the Bears and rushed 46 times for 203 yards (4.4 YPC) and one touchdown.
Trevathan, 31, is a former sixth-round pick of the Broncos back in 2012. After four years in Denver, Trevathan signed a four-year, $24.5 million contract that includes $12 million guaranteed with the Bears.
Chicago brought him back last year on a three-year deal worth $21.75 million.
In 2020, Danny Trevathan appeared in all 16 games for the Bears and recorded 113 tackles, one sack, a forced fumble and five pass deflections.