Elliott is expected to appeal the ruling and must do so within three business days, ESPN's Adam Schefter reports.
The NFL's investigation into Elliott's off-field actions stretches back over a year, before Elliott had taken a snap in the NFL. In July 2016, an Ohio woman accused Elliott of assault. It later came to light that the same woman called police and accused Elliott of assault in February 2016.
Elliott hasn't been charged with a crime, but four external advisors assisting commissioner Roger Goodell in evaluating whether Elliott violated NFL policy believed there was "substantial and persuasive" evidence that the running back engaged in physical violence against his accuser.
In the ensuing months after the July 2016 accusation, Elliott drew the ire of Cowboys owner Jerry Jones when he was spotted visiting a marijuana dispensary in Seattle. He also exposed a woman's breast at a St. Patrick's Day parade, but those incidents didn't factor into the six-game ban, according to NFL Network's Tom Pelissero.