He is among the players awaiting disciplinary decisions from NFL commissioner Roger Goodell and the league office, and based on information from league sources, Brent will not be playing for the Cowboys -- or any other team -- when the season opens.
"He's not just going to walk back onto the field," a source said.
Brent spent 45 days in rehab after his release from jail for the drunken-driving death of teammate Jerry Brown. Brent is also serving 10 years of probation.
The league suspended wide receiver Donte' Stallworth for the entire 2009 season after he pleaded guilty to a DUI manslaughter charge in Florida.