Dallas Cowboys coach Mike McCarthy said Friday that left tackle Tyron Smith will have surgery next week on his neck and is out for the season.

Smith suffered the injury during a practice after Dallas' season opener and missed the next two games. He returned for last Sunday's loss to the Browns and played every snap.

The Cowboys have not had right tackle La'el Collins all season, and he had season-ending hip surgery Wednesday.

Smith has missed games in each of the past five seasons, dealing with back, hamstring, knee and elbow injuries in addition to the neck injury.

Brandon Knight started in Weeks 2 and 3 for Smith against the Atlanta Falcons and Seattle Seahawks, but he took over last week at right tackle after undrafted rookie Terence Steele struggled. Knight could move back to left tackle, with Cameron Erving, who is eligible to return off injured reserve this week, and Steele battling for the right tackle spot.

Erving suffered a knee injury in the season opener. The Cowboys added veteran Jordan Mills to the practice squad late last week. He has 84 career starts at right tackle.

ESPN's Todd Archer contributed to this report.