Former Dallas Cowboys running back Marion Barber has died at the age of 38, the team announced Wednesday.

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

Marion was an old-school, hard-nosed football player who ran with the will to win every down.

He had a passion for the game and love for his coaches and teammates.

Our hearts go out to Marion's family and friends during this difficult time.

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,

Barber's best season in the NFL came in 2007 when he rushed for 975 yards and 10 touchdowns...

while adding two more scores through the air en route to Pro Bowl honors.

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