NFL head coaches are going to test out the new pass interference rule because they can. The NFL updated their rulebook, allowing coaches to challenge a pass interference whether it's called or not.
Minnesota Vikings head coach Mike Zimmer is going to be one of the coaches to test the updated penalty in the pre-season, as he said, via Pro Football Talk‘s Mike Florio;
My flag is probably going to get emptied out in the preseason. I think we just have to figure out how they’re going to call it and how they’re going to do it. You know, it’s gone round and round and round so many times. Now it has to be, what’s the words, ‘clear and obvious’ or something like that. — So the video that I’ve watched, they sent us another video a couple days ago, had two plays on it, the second play they didn’t even say if it was pass interference or not. I think it’s a work in progress. They went quick with it. They went quick with it and passed it at the owner’s meetings and they’re finding out there’s some possible unintended consequences coming about.
Zimmer doesn't quite know how the pass interference rule works yet, though he sees it being eventually worked out.
If I touch him like that before the ball gets there, is that pass interference?” Zimmer said. I don’t know, we’ll have to see. That’s why I’m probably going to throw my flags. It will be fun.
Oh, it will be something that starts with an F and a U. And quite possibly that ends with ‘up.'
The pre-season will be fun to watch for many reasons — most notably that football is back — but chief among them is how the pass interference rule works out. Zimmer won't be the only coach to spam the flag, as his NFC North rival Matt Patricia will do the same thing.