Per Rick Stroud of the Tampa Bay Times, the Buccaneers placed Brown on the reserve/COVID-19 list on Wednesday.
Stroud noted the seven-time Pro Bowler needs to have two negative COVID-19 tests 24 hours apart before he is eligible to play.
Head coach Bruce Arians announced on Sept. 2 that the entire Bucs organization, including players and coaches, has been vaccinated. The Atlanta Falcons are the only other team with a 100 percent vaccination rate to date.
Brown signed with the Bucs last October and made his team debut in a Week 9 game against the New Orleans Saints after completing an eight-game suspension for multiple violations of the NFL's personal conduct policy. He recorded 45 catches for 483 yards and four touchdowns in eight regular-season games, and he added two more scores during the team's run to the Super Bowl LV title.
The 33-year-old Miami native opened last year's playoffs with a touchdown catch against the Washington Football Team in the Wild Card Round, but he suffered a knee injury during the divisional round and was ruled out of the NFC Championship Game as a result. He returned for the Super Bowl.
Brown carried that momentum over to the 2021 season. He finished with 121 yards and one touchdown on five receptions in a 31-28 win in Week 1.
The silver lining for Tampa Bay is its terrific pass-catching depth. Wide receivers Mike Evans and Chris Godwin along with tight end Rob Gronkowski lead the way, while Scotty Miller and Tyler Johnson are likely to receive some extra snaps if Brown can't play Sunday.
Brown should return to his standard role in three-receiver sets once he returns from the reserve/COVID-19 list.