Former Dallas Cowboys running back Marion Barber III has died at the age of 38.

We are heartbroken by the tragic death of Marion Barber III," the Cowboys said in a statement.

The cause of Barber's death is not currently known.

Barber played in the NFL from 2005 to 2011.

spending his first six years with the Cowboys.

who selected him in the fourth round of the 2005 draft out of the University of Minnesota.

Barber's best season in the NFL came in 2007.

At the end of the 2010 season, Barber signed with the Bears.

and spent his final season in Chicago before announcing his retirement in March 2012.

Our hearts go out to his family and friends.