The Pittsburgh Steelers have built a structure to cover one of their three fields in an effort to prevent spying.

The structure consists of four black pillars about two stories high and for practice sessions the team can raise an attached giant black tarp.

"I'll leave that somewhat mystical for you guys to hypothesize about the origins of that and its use, and at some point we'll address it the right way," Mike Tomlin said. "I know how it is, man. This is interesting times, drones and so forth. We do what we've got to do to prepare and get ready to play to have a level and fair competitive playing field."