So this was a strange one.
With the Dallas Cowboys driving against the Green Bay Packers on the first quarter of their game, Dallas wide receiver Brice Butler was called for an unsportsmanlike conduct penalty.
It wasn't for excessive celebration or fighting with an opposing player, offenses you might identify with unsportsmanlike conduct.
No, he joined the huddle and then left the field without participating in the play. Here's an explanation:
Since the Cowboys has just completed a 22-yard pass play, that was called back, and the team was penalized 15 yards. That means Butler's miscue cost the Cowboys 37 yards.
Remember, NFL defenses relay on matchups, so this rule appears to be a fairness issue. You can't have players running in and out because defenses wouldn't know what to play.
Still the rule and penalty confused a whole lot of people.