Washington Commanders defensive end Dorance Armstrong won't play Sunday against the visiting Carolina Panthers because of a rib injury, coach Dan Quinn said Friday.

Quinn also ruled out rookie safety Tyler Owens (shin) and said starting running back Brian Robinson Jr. (knee) is "trending in the right direction" and a decision will be made this weekend. Robinson did not practice last week and has been limited this week.

Armstrong, 27, was injured in last Sunday's 30-23 loss to the host Baltimore Ravens. He did not practice Wednesday and Thursday.

"He had a good week but he's not there yet," Quinn said.

Armstrong has started all six games for Washington (4-2) and has 12 tackles, three sacks, nine quarterback hits and one forced fumble.

He signed as a free agent with Washington in March after six seasons with the Dallas Cowboys, who had selected him in the fourth round of the 2018 NFL Draft out of Kansas.

Armstrong has 181 career tackles, 26.5 sacks, 25 tackles for loss, 57 QB hits, four forced fumbles and four fumble recoveries in 99 games (20 starts).

Owens, 23, was an undrafted free agent out of Texas Tech who has played in four games on special teams and has two tackles. He did not practice on Wednesday and was limited on Thursday.

Robinson, 25, leads the Commanders in rushing with team highs of 325 yards, 73 carries and five touchdowns in five games. He missed the game against the Ravens last Sunday, when Washington was limited to 52 rushing yards on 18 attempts.

He has 1,855 career rushing yards with 12 TDs and 496 receiving yards with five TDs in 32 games (29 starts) since Washington picked him in the third round of the 2022 draft out of Alabama.

--Field Level Media