Trevathan (knee) was placed on injured reserve Friday, Larry Mayer of the Bears' official website reports.
Trevathan missed the first four games of the season on injured reserve due to a knee injury, so he will now be out for the remainder of the season after landing on injured reserve for the second time this year. The 10-year veteran linebacker appeared in five games this season, registering 19 tackles. In a corresponding move, outside linebacker Cassius Marsh was elevated from Chicago's practice squad to its active roster.