There is no Sixth Man of the Year award in the NFL. Even if there was, they’d have to name it 12th Man of the Year, and they might run into copyright laws with the Seattle Seahawks, or Texas A&M if you stand by that (shout out Ben Baby).
But there is something to be said for a player who consistently performs well when called off the bench. Like a running back who adds a spark for 10 plays a game, or an edge rusher who specializes on third downs.
What about a rookie offensive lineman who was benched earlier in the year?