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Just as people were raving about Dallas Cowboys‘ second-year running back Lance Dunbar, he was added to the growing list of Cowboy players hit with injuries.

Dunbar will miss the next 3-4 weeks with a sprained left foot suffered Saturday against the Arizona Cardinals, and may not be ready in time for the season opener September 8 vs. the New York Giants – which is the NFL‘s first Sunday night regular season game this year.

Related: Washington Redskins Plagued by Quarterback Injuries

The injury is a big blow to Dunbar, a guy who is second on the depth chart behind DeMarco Murray. He was looking to solidify his spot as the clear backup running back on this team, and was doing very well by all accounts.

One positive to take away from it from the Cowboys’ standpoint — if there even is a positive — is that the team does have depth at the position and it gives Phillip Tanner, a second year player out of Middle Tennessee State, and Joseph Randle, a rookie out of Oklahoma State, chances to impress and possibly win that no. 2 job at least for Week 1, in the case that Dunbar cannot go.

Both Tanner and Randle had great games in the Hall of Fame Game. Randle rushed for 70 yards on 13 carries, and Tanner rushed for 59 yards on 10 carries. Since that game though, the Cowboys’ running game has slowed. The next week, Tanner and Randle combined for 41 yards on 15 carries and one touchdown, while the team as a whole ran 16 times for 44 yards against Arizona.

A large part of the team’s inability to run the ball effectively is on the offensive line’s play, so we really have only the first game to truly judge their talent.

But with Dunbar out now, there’s two more preseason games and a potential season opener for both the Cowboys’ backup running backs to show what they can do.

Jake Carapella is a Dallas Cowboys writer for RantSports. Follow him on twitter @JKCSports1.