The SBA By-Laws state:

• Any player who is eligible to play in the junior domestic competition may play in no more than one age group above their current age competition. Example:
  A Player eligible in U14 can only play up to U16 competition. That player cannot play in the U18 competition.
• A Junior fill in player may play up to (3) games a season in a higher grader of the same age group in a junior competition. Once the player plays a fourth game in a higher grade, they are no longer eligible player in the lower grade. Junior players are not permitted to play in a grade lower than the team they have registered to play in.