Updated

Dallas Cowboys running back Lance Dunbar has a sprained left foot, putting his availability for the season opener in jeopardy.

Dunbar had a protective boot on his foot Monday when the Cowboys returned to practice at Valley Ranch after the first month of training camp in California.

Coach Jason Garrett says Dunbar is certainly out his week and will be day to day after that.

The second-year running back was making an impact during camp. In Saturday's loss at Arizona, Dunbar had a 43-yard reception and another 18-yard catch. He fumbled at the end of the long catch.

Garrett hopes that it's "just a mild setback" for Dunbar.

Dunbar has eight rushes for 45 yards and six catches for 83 yards in three exhibition games.