St. Louis Rams fullback Brit Miller has officially been placed on injured reserve.

A linebacker at the University of Illinois, Miller (6-0, 243) had signed with the Carolina Panthers as an undrafted free agent in 2009. Miller was converted to fullback by the San Francisco 49ers last summer, appearing in five games at the end of his rookie season.

Waived by the 49ers in September, Miller joined the Rams' practice squad in Week 2.

Activated to the 53-man roster in October, Miller appeared in nine games and has 9 tackles on special teams. Miller started the last two games, but suffered a torn ACL in his right knee during Sunday's loss to the Kansas City Chiefs.

With Miller on IR, veteran Mike Karney is expected to return to the starting lineup after being a healthy inactive the last few weeks. The Rams have not yet made a corresponding move to fill Miller's roster spot.