Not only did the Steelers require the services of Avery Williamson, still just weeks into his tenure with the team, this past Sunday, they also called upon him to wear the green dot on his helmet, which signals that he has the earpiece that relays the defensive calls from the sidelines. He is responsible for relaying the call to the rest of the unit and setting the defense.
It’s not a responsibility that you can entrust to anybody, of course. The player taking on the task has to have a very solid working understanding of the defense that is being run, and he also has to be adjusted enough to be able to carry out that assignment without it affecting his performance.