The Dallas Cowboys downgraded Pro Bowl left tackle Tyron Smith from questionable to out for Sunday's game against the Atlanta Falcons due to back and groin injuries Saturday, according to Ian Rapoport of NFL Network.
Smith has battled a lingering back injury all season, but was able to play in the first eight games of the campaign.
Chaz Green will likely start in Smith's place.
The Cowboys will now be without two of their key offensive players, as Ezekiel Elliott is set to serve the first of a six-game suspension.
