No, participation in a tournament is strictly optional and is up to each individual team. Just about every recreational tournament allows for guest players to cover these situations. However, you MUST invite each existing team member to attend the tournament. If a player chooses not to attend a particular tournament, you may then pick up guest players. At no time may a team go above their maximum allowable roster size.  Karen Owens Soccerfest for 4U-8U is part of the season and not an official tournament, but more of an end of season event that includes games.