The Cowboys faced an early fourth-and-one from the Washington 27. Ezekiel Elliott was met in the hole by Washington safety Maurice Smith.
Both stayed on the ground.
Elliott limped off but returned after sitting out one play.
Smith, though, wasn’t as fortunate. He was loaded onto a backboard and carted off.
Smith waved as he was placed on the cart and gave a thumb’s up before the cart departed up the tunnel, drawing cheers from the crowd.
The team announced Smith will not return after being diagnosed with a concussion.
The Cowboys, needing help from the Giants to make the postseason, have a 3-0 lead on a 28-yard field goal by Kai Forbath with 7:41 remaining in the first quarter.
The 10-play, 26-yard drive was set up by linebacker Jaylon Smith’s interception of a Case Keenum pass intended for Jeremy Sprinkle.