The Dallas Cowboys' struggling defense suffered a blow on Friday as cornerback Trevon Diggs was ruled out of Sunday's NFL game against Washington after an accident at his home put him in concussion protocol.

"Trevon Diggs came in this morning with some concussion symptoms after having an accident in his home," head coach Brian Schottenheimer said.

"He's been checked out by our doctors, and he's in the protocol, and he'll miss the game."

Schottenheimer said the team was still "gathering information" on the circumstances that led to the injury, which happened on Thursday night.

Through six weeks of the season the Cowboys defense ranks last in the league in passing defense and 31st in points allowed.

Diggs, who had surgery on his left knee in January as he battled a right knee injury this season, playing in all six games with four starts.

The length of concussion absences varies by player, depending on how long symptoms persist.

The Cowboys go into the NFC East division clash with the Commanders lying third in the division at 2-3. The 3-3 Commanders are second behind the 4-2 Philadelphia Eagles.