Johnson was diagnosed with a concussion after exiting Thursday's 21-7 loss to the Browns following a helmet-to-helmet hit from Cleveland safety Damarious Randall, Adam Schefter of ESPN reports.
Pittsburgh ended up losing both of its top two receivers to concussions in the contest, as JuJu Smith-Schuster exited in the first half with the head injury before Johnson followed him to the locker room in the third quarter. Johnson's concussion may have been the more significant of the two, as Schefter notes the rookie was bleeding from his ear after being hit by Randall. Johnson will need to clear the NFL's five-step protocol before he's able to play again, but the fact that Pittsburgh's next game won't come until Nov. 24 in Cincinnati should aid his efforts.