IRVING -- The Cowboys have signed linebacker Brady Poppinga to fill the void left by linebacker Bruce Carter, who's been placed on the injured reserve. Carter suffered a dislocated elbow Thursday against the Redskins and will have surgery this week.
"He was playing awfully well," said Cowboys head coach Jason Garrett. "He was playing really well early on in the season inside with Sean Lee and really developed into a really good player."
Carter becomes the fourth defensive starter lost for the season, joining fellow linebacker Sean Lee, safety Barry Church and defensive lineman Kenyon Coleman.
Poppinga has played seven years in the league after being drafted by the Packers in the fourth round in '05.
The injury means veterans Dan Connor and Ernie Sims, along with Popinga, will fill the middle for the Cowboys defense moving forward. Sims joined the team four weeks ago.
Defensive back Orlando Scandrick will also miss some time with a broken hand he suffered against the Redskins. He had surgery last week and there's not a timetable for his return.
The Cowboys also signed receiver former Redskin and Dolphin receiver Anthony Armstrong, who also played for the Arena League team here in Dallas.
To make room, the Cowboys cut receiver Andre Holmes. There was hope in training camp Holmes could develop into the team's third receiver, but he's had next to no impact offensively this season and only slightly more than that on special teams.