Burfict was initially diagnosed with a stinger after leaving Sunday's win over the Atlanta Falcons in the second half. Concussion-related symptoms didn't surface until after the game, according to Bengals.com writer Geoff Hobson.
The 6-foot-1, 248-pounder also suffered a concussion in the Bengals' Week 1 win over the Ravens. Burfict will have to go through the NFL's concussion protocol before returning to action.
The 23-year-old recorded an NFL-high 115 tackles and three sacks over 16 games last season.
The Bengals (2-0) host the Tennessee Titans on Sunday.
- Chris Johnson