The Buffalo Bills signed cornerback Crezdon Butler off the Arizona Cardinals' practice squad and signed free agent offensive lineman Thomas Welch. They replace cornerback Terrence McGee and offensive tackle Erik Pears, who were placed on injured reserve Tuesday. Butler has spent time with the Cardinals and Washington Redskins this season. A fifth-round pick by the Pittsburgh Steelers in 2010, he has appeared in eight career games. Welch was released by the Philadelphia Eagles before the start of the season. He was a seventh-round pick by the New England Patriots in 2010 and spent his rookie season on the Minnesota Vikings' practice squad before being promoted. He appeared in five games for the St. Louis Rams last season and three with the Patriots, including one start.