Trevon Diggs will miss the Cowboys' showdown with the Commanders on Sunday after suffering an unspecified accident at home.
Dallas head coach Brian Schottenheimer did not disclose details of the incident, which occurred on Thursday night.
Schottenheimer only revealed that the cornerback had concussion symptoms when he reported to the team facility Friday.
Diggs was evaluated by the Cowboys medical staff and placed in concussion protocol, meaning he won't play against Washington this weekend.
Schottenheimer said he didn't have any other information on what happened to Diggs, who played in all of Dallas' first six games.
The cornerback had spent the offseason rehabbing a major knee injury for the second consecutive year.
Trevon Diggs will miss the Dallas Cowboys' showdown with the Commanders on Sunday
The cornerback had concussion symptoms when he reported to the team facility Friday
'This is the NFL. If you're unsure what's going to happen,' coach Brian Schottenheimer said
'It's part of the business. It's unfortunate,' Schottenheimer said. 'This is the NFL. If you're unsure what's going to happen, just wait because something is going to happen.
'You deal with it. The biggest thing is just the concern for Trevon and (is) he OK. And it seems like he is.'
The Cowboys (2-3-1) are last in the NFL in yards allowed and passing yards allowed heading into the meeting with the Commanders and reigning AP NFL Offensive Rookie of the Year Jayden Daniels.
Washington will be without top receiver Terry McLaurin, who will miss his fourth consecutive game with a quadriceps injury.
Diggs' sudden absence comes with the Cowboys expecting star receiver CeeDee Lamb to return after missing three games with a high ankle sprain.