Trailer released for documentary on former Saint Gleason's battle with ALS

Get the tissues ready.

New Orleans Saints folk hero Steve Gleason has had a very public battle with ALS since being diagnosed in 2008 and now he's ready to tell the private story.

Gleason and his wife decided to have a child after his diagnosis with the knowledge that he or she may never know who their father really was. The former defensive back started recording a video diary for his unborn son as a way to communicate with him after the debilitating disease took away his speech and movement.

These home videos serve as a major part of his documentary "Gleason" which debuted in January at the Sundance Film Festival and will open in select theaters July 29th, according to Yahoo! Movies, who helped produce the film.