The cause of death was suicide by hanging, the Philadelphia coroner told The Denver Post on Monday.
Robinson went undrafted in 2011 and signed with the Pittsburgh Steelers. He played in 12 games as a rookie. The Steelers traded him to the Philadelphia Eagles in exchange for Felix Jones before the start of the 2013 season. Robinson was released a week later and signed with the Denver Broncos.
He played six games in Denver in 2013 before he was waived and signed by the San Diego Chargers. Robinson played two games for San Diego, was cut and signed with the Washington Redskins. He played two games for Washington.
Robinson did not play in 2014 and signed a contract with the Canadian Football League's Hamilton Tiger-Cats last month.
Robinson, a Harrisburg, Pennsylvania, native, played in every game over his four seasons at Temple University. He started all 25 games in his junior and senior seasons and was a two-time All-MAC selection.
"It deeply saddens all of us to share with you that Adrian Robinson Jr. passed away last night at the age of 25," Robinson's agency, Symmetry, said in a statement on its Facebook page. "Adrian was a beloved father, son, brother, friend and teammate. We ask that you please respect his family’s privacy during this difficult time, and especially keep his daughter Avery Marie in your prayers. Thank you for all of your support and consideration."
- Dan Gartland