Tampa Bay placed Gregory of the reserve/did not report list Tuesday, Greg Auman of Fox Sports reports.
The Buccaneers made the transaction after Gregory wasn't present Tuesday for the first day of training camp. The 31-year-old was also absent from the Buccaneers' three-day minicamp in June, and he currently has an open lawsuit against the NFL and the Broncos for discrimination due to a $500,000 fine he received last season for using THC.