Sewell was concussed during Saturday's preseason win against Cleveland, Courtney Cronin of ESPN.com reports.
Sewell was hurt during a kickoff and spent a few minutes on the ground before exiting under his own power. He finished the game with three tackles (one solo). Sewell will need to clear the league's concussion protocol before returning to full-contact practice or playing in a game. He's trying to earn a role with Chicago as a depth linebacker and special-teamer.