League Rules:
Each league has similar playing rules.  This makes sense, since they are all based upon The Laws Of The Game.  However, almost all leagues have slight variations in their application of the Laws.   It’s important that you know the rule set for any league in which you are assigned games. Go to their website and brush up on their application of the Laws and note specific rule differences.Pay particular attention to the league's substitution rules.  For 2016, USSF has made changes to a number of the rules governing small-sided games.  Make sure you look for how the league is implementing these rules.  You will find slight variations in how they are presented.