If he was in pads and standing on a sideline for a game then I would consider it "Game Used". If he did not dress but wore it on the sideline, then I would call it "Game Issued".

I think, when you start asking the question, does wearing a jersey for a backup qb make it game worn, it opens a can of worms...

What about a kicker who kickoffs and kicks the ball for a touchback and never steps foot back on the field because his team gets shut out...does that really count as well?

Too many questions and what if's...keep it simple...If the player is in pads, then the jersey in "Game Used".