Head coach Mike Tomlin told reporters that Watts (undisclosed) suffered a "stinger" in Saturday's 24-17 preseason loss to the Lions, Brooke Pryor of ESPN.com reports.
Watts sustained the injury on the third-to-last play of the game. He finished the contest with three tackles (two solo). Watts is battling for a spot on the Steelers' 53-man roster in a depth role in the secondary.