Brown has been battling a knee bone bruise, putting his status in doubt for Sunday's game against the Jacksonville Jaguars and possibly beyond, a source told ESPN's Adam Schefter.
The second-year wideout didn't practice Thursday after training on a limited capacity Wednesday.
Brown racked up five receptions for 39 yards in the Titans' 16-14 season-opening victory over the Denver Broncos on Monday. He led the team with 52 catches, 1,051 receiving yards, and eight touchdowns as a second-round rookie last season.
Fellow pass-catcher Corey Davis, who topped Tennessee with 101 receiving yards on seven receptions against the Broncos, returned to practice Thursday after missing Wednesday's session with a hamstring injury.