The Redskins have signed linebacker Rob Jackson from the practice squad and re-signed defensive lineman Darrion Scott, the team announced on Wednesday.
Jackson and Scott take the roster spots of defensive linemen Phillip Daniels and Ma'ake Kemoeatu, who have both been placed on injured reserve.
In addition, the Redskins have signed defensive lineman Rashaad Duncan and offensive tackle Xavier Fulton to the team's practice squad and released offensive tackle Jacob Bender from the practice squad.
Jackson has spent the first 14 games on the Redskins' practice squad.
The 6-4, 225-pounder transitioned from defensive end to linebacker last offseason.
Jackson, a third-year player and 2008 seventh-round draft pick by the Redskins, has played in eight games in his career, posting one tackle.
Scott spent last offseason and training camp with the Redskins but he was released at the end of preseason.
Scott, 6-3 and 310 pounds, has played in 48 career NFL games, with 28 starts, all with the Minnesota Vikings from 2004-07. He has posted 157 tackles, 9.5 sacks, one forced fumble and three fumble recoveries in his career.
Duncan , 6-2 and 315 pounds, has had NFL stints with the practice squads of the Tampa Bay Buccaneers, Carolina Panthers and Buffalo Bills.
He entered the league as an undrafted rookie free agent on May 1, 2009.
Duncan played college football at Pittsburgh, where he appeared in 48 games with 35 starts. As a senior, he logged 55 tackles and 1.5 sacks as a nose tackle.
Fulton, 6-5 and 301 pounds, has spent time on the practice squads of the Indianapolis Colts and San Francisco 49ers earlier this year.
He was originally drafted by the Tampa Bay Buccaneers in the fifth round (155th overall) of the 2009 NFL Draft. He spent his entire rookie season on injured reserve.
He played college football at Illinois, where he appeared in 40 games with 35 starts. He started 25 games at offensive tackle during his junior and senior seasons.