The Dallas Cowboys will be without Dak Prescott's blindside blocker Sunday against the Atlanta Falcons.
Tyron Smith is dealing with a neck injury sustained during practice this week and has been ruled out, NFL Network's Jane Slater reported.
The team later officially marked Smith inactive.
The seven-time Pro Bowler was officially listed as questionable, with the Cowboys brass indicating a decision could come down to the wire. Unfortunately for Dallas, Smith couldn't go in the end.
Missing the 29-year-old left tackle is a massive blow to the Cowboys, who are already without right tackle La'el Collins and backup OT Cam Erving -- both on IR.
Undrafted rookie Terence Steele started Week 1 at right tackle, and now the Cowboys will have to dive even deeper into their pool of linemen.
Needing a victory to avoid an 0-2 start, the Cowboys' blocking could be a problem against a Falcons team that cobbled together three sacks in Week 1, with Grady Jarrett, Takk McKinley and Dante Fowler combining for 10 QB hits. Expect Prescott to get the ball out quick Sunday to help try to negate blocking issues that are sure to come with starting multiple backups at the tackle spots.