ORCHARD PARK, N.Y. (AP) — The Buffalo Bills have placed starting guard Chris Williams on the injured reserve, ending his season.

Williams missed the Bills last two games with a back injury.

A first-round pick of the Chicago Bears in 2008, Williams spent parts of five seasons with the team before moving to St. Louis in 2012. Williams joined the Bills as a free agent in March, signing a four-year deal worth $13.5 million.

Buffalo promoted safety Kenny Ladler to the 53-man roster. He joined the Bills as an undrafted free agent out of Vanderbilt but was released before the start of the regular season.

Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.