One of the responsibilities that typically fall into the lap of a starting middle linebacker is donning the green dot on the back of their helmet during games, a distinction that means that they are the one defensive player on the field who has a radio headset in his helmet. That allows him to receive the calls from the defensive coordinator, sometimes via another defensive coach on the sideline.

That conversation is a one-way street, since the players are not permitted to have microphones to talk back. But it is an important one nonetheless, as the player with the green dot is the one who gets the defensive play call verbally and must relay it to the rest of the defense. For more on how that process works, I recommend you read this story I did back in Baltimore a couple of years ago.

So how does this relate to the Vikings? Well, head coach Mike Zimmer has yet to choose a starting middle linebacker between Jasper Brinkley and Audie Cole. And regardless of which one he picks, they are not expected to play in the nickel and other sub packages, meaning they will only end up being on the field about 40 percent of the time. So giving the green dot to the Mike isn't going to fly.

Zimmer could have chosen to give it to starting safety Harrison Smith, but when TCF Bank Stadium gets worked up in anticipation of a big third-down play, it would be difficult for Smith to yell out the calls loud enough from the secondary for the guys in the trenches to decipher what he was saying.

That left two other choices: Chad Greenway and Anthony Barr, who both stay on the field in the nickel package. Of course Zimmer was going to delegate those duties to the veteran, not a rookie.

"I think we're pretty solid there," Zimmer said when asked if he is still trying to figure out a plan.

Zimmer, who must have forgotten that we are running out of new stuff to talk about here in the dog days of late August, seemed surprised that I was asking him about who would wear the green dot.

"Is that important? It's a news story today?" Zimmer said playfully (I think, at least). "Yeah, he's been doing it. I wish 11 of them could have it, though. Have blue dots, green dots, red dots."