FRISCO, Texas -- The Dallas Cowboys put Cameron Erving on injured reserve with a sprained knee Friday, ending the tackle's season because it's his second stint on IR.
Erving, who missed five games early after injuring a knee in the opener, went out again on the first Dallas drive in a 41-16 loss to Washington on Thanksgiving.
The Cowboys signed Erving as the backup tackle, but seven-time Pro Bowl left tackle Tyron Smith was limited to two games before season-ending neck surgery while right tackle La'el Collins never played this season before having hip surgery.
Dallas is also without four-time All-Pro right guard Zack Martin. He injured a calf muscle a few plays after Erving's injury on the same drive against Washington. Martin is on IR but not officially out for the season because he could return for the final two games.
Rookie center Tyler Biadasz (hamstring) could return from IR for Sunday's visit to Cincinnati.
The Cowboys could have four starters in their first or second seasons on the offensive line if Biadasz returns and starts in place of veteran Joe Looney.