HS rules don't necessarily apply because in NJ, the NJSIAA - the organization that oversees HS sports - does not cover MS sports. Each individual MS league is free to make up their own rules. In the MS league that our association works, the league rules specifically call out that an EH is allowed and that position is to be just like a defensive position. Your league may have different rules. The best thing to do is make sure it's discussed at ground rules so that everyone's on the same page.