Former Dallas Cowboys running back Marion Barber III died of heat stroke, according to the Collin County Medical Examiner's Office (via USA Today). Frisco, Texas, police found Barber dead in his apartment June 1. His death was ruled an accident.

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

Barber, who would have turned 39 on June 10, was drafted by the Dallas Cowboys in the fourth round of the 2005 NFL Draft. Barber spent seven seasons in the NFL, six with the Cowboys from 2005-2010 and one with the Chicago Bears in 2011. He made the Pro Bowl in 2007 while with the Cowboys.

He finished his career with 4,780 rushing yards and 53 rushing touchdowns to go along with 1,330 receiving yards and six receiving touchdowns.