Tafur added that Bryant hasn't been notified by the league about anything regarding a suspension.
Last week, Michael Gehlken of the Las Vegas Review-Journal reported that Raiders officials feared NFL discipline was "imminent" for Bryant.
Gehlken added that while those within the organization didn't comment on the situation, it was believed that Bryant's possible suspension pertained to the NFL's substance-abuse policy.
Bryant was suspended for four games in 2015 due to a substance-abuse policy violation, and he was then suspended for the entire 2016 campaign due to multiple violations, per Spotrac.
The 26-year-old wideout returned last season to appear in 15 games for the Pittsburgh Steelers. He finished with 50 receptions for 603 yards and three touchdowns.
Oakland acquired him in an offseason trade that sent a third-round pick to Pittsburgh.
Bryant is set to enter the final year of his contract, and he is expected to be a key part of a talented receiving corps that also includes Amari Cooper and Jordy Nelson.