Armstrong is slated to sign with the Commanders on Wednesday, Jeremy Fowler of ESPN.com reports.
Armstrong recorded 38 tackles (20 solo) including 7.5 sacks with a pass defended over 17 regular-season games in 2023.
Armstrong recorded three tackles (two solo) and one sack in the Cowboys' Week 10 victory over the Giants.
Armstrong recorded three tackles, including two sacks, in Sunday's 40-0 rout of the Giants.
Armstrong (hamstring) did not practice Thursday, Calvin Watkins of The Dallas Morning News reports.
Armstrong (hamstring) was a full participant at Monday's practice, Todd Archer of ESPN.com reports.
Armstrong is dealing with a hamstring injury, Todd Archer of ESPN reports.
Armstrong recorded 33 tackles (17 solo), including a career-high 8.5 sacks, through 17 regular-season games in 2022. He added a forced fumble and two fumble recoveries.
Armstrong (knee) has been ruled active for Saturday's game versus Philadelphia, Michael Gehlken of The Dallas Morning News reports.
Armstrong (knee) returned to the field after exiting Sunday's game at Jacksonville, Michael Gehlken of The Dallas Morning News reports.