NFL sidelines- maroon shirt/officials cap- who is it?

[HLin NC]

This season, I've noticed an official on the sideline at NFL games, usually near the chains. He wears a maroon shirt (or in the case of today's Steelers/Titans game, a maroon jacket) and a regular striped NFL officials cap. I think the socks look to be regular college/HS pattern but don't recall for sure.

I know the NFL doesn't use alternates until the playoffs. I've thought maybe he is the ECO like the SEC but he holds nothing in his hands from what I've seen.

Someone on Ed Hoculi's son's board said it was the person who oversees the kicking balls but again, I've never seen any of them hold anything or actually DO anything in the tv shots I've seen.

Anybody know what kind of gig this is? Doesn't look horribly taxing.