Need a football? Well I've got a "K" on my chest, here you go!

I was watching MNF last night and noticed the guys on the sidelines that hand the footballs to the refs have these big ass smocks with a “K” on them. What does the “K” stand for?

Keeper?

I’m wondering it this isn’t a big clue to what’s going on:

Perhaps there are separate ball boys handling the for-kicking-only footballs?

Correct.

Cool, now I can amaze and impress my friends and family. Thanks guys.

What is the difference (if any) between the different types of balls?

The ordinary game balls are not maintained by the officials before the game. AFAIK, both teams can go through their warm-ups with game balls before the game.

However, the kicker “k” balls (are supposed to) come sealed from the manufacturer, and are kept in the officials’ locker room before the game. This article touches on the purpose of having separate balls for kickers:

Obviously, the “K” balls use cattle-leather coverings, not pigskin, and are therefore Kosher. Duh.

What?