Bryant's camp is confident that it has a chance to win the appeal, which is expected to be heard in the next couple of weeks, according to sources.
This is one of the main reasons that the Raiders took Bryant back on a contract that pays him from week to week. For now, Bryant's appeal looks like it could buy him a few weeks on the Raiders' roster, and possibly even more, depending on how the league rules. But appeals are notoriously tough to win.
Bryant has retained New York attorney Peter Ginsberg to assist in his appeal, a source told ESPN's Dan Graziano.
The Raiders re-signed Bryant this week after releasing the talented but troubled receiver on Sept. 1. His latest potential suspension stems from another violation of the NFL's substance abuse policy.
The Raiders (0-1) visit the rival Denver Broncos on Sunday after their disappointing loss this past Monday in coach Jon Gruden's return to Oakland. Raiders receivers were shut down in a 33-13 loss to the Los Angeles Rams, with Amari Cooper catching one pass on three targets for 9 yards and Jordy Nelson getting three receptions on four targets for 23 yards.
Bryant, 26, was suspended for the entire 2016 season for violating the NFL's substance abuse policy, but he returned to haul in 50 receptions for 603 yards and three touchdowns last season.
ESPN's Paul Gutierrez contributed to this report.