This page explains how jersey numbers are assigned

Players will be assigned a number when they first join, and should be able to retain that same number as long as they play with Wayland Youth Lacrosse.  Once a number is assigned, it will not be given to another player in the same age group.  This will eliminate the confusion of watching a game and having multiple players with the same number.

When you order your jersey you have the opportunity to request a number.  However, if the number requested is already in use, another number will be assigned.

To determine which numbers are available for your player, see the chart below.  In the row with the player's grade in school is the range of jersey numbers that will be assigned.  For example, all 5th grader's jerseys will be numbered between 10 and 39.