Cowboys RB Dunbar could be out for a month with injury

IRVING, Texas -- Second-year running back Lance Dunbar was emerging as a dynamic complement to Cowboys starter DeMarco Murray. But Dunbar showed up at Monday's practice with a protective boot on his sprained left foot, with the possibility of being sidelined for a month, according to a Cowboys source.

In this preseason, the smallish Dunbar has eight carries for 45 yards and six receptions for 83 yards. Up until the injury, his work is marred only by a fumble at the end of an explosive catch-and-run against the Cardinals on Saturday.

While Dunbar was slated to possibly earn regular-season snaps as a third-down back, Dallas does have depth at the position with fifth-round pick Joseph Randle and power back Phillip Tanner also available.