Clausen sustained a concussion in Saturday's preseason outing, Jeff Dickerson of ESPN Chicago reports.

EDGE Analysis

After Clausen's removal from the game due to a head injury, initial tests ruled out a concussion. However, as is often the case with such ailments, his symptoms were delayed, according to head coach John Fox. Clausen will now enter the league's concussion protocol, which should afford David Fales and potentially Shane Carden plenty of snaps in Thursday's final exhibition.