The OPT (One player type) group is designed to cater for teams with only one player type in. This may seem abit strange but it takes player advancment to a whole new level as the skills you choose may be the only ones you have in the entire team. Anyone and everyone is welcome to join but there is a number of rules for team creation;

1) All players must be of the same type (lineman, goblin , werewolf, etc).
2) You can only buy players of that same type.
3) All team additions are allowed (including wizards).

Obviously Fumbbl forces you to have eleven players at the start which can be annoying if your going for a less common player type. To deal with this problem just retire all unwanted members of the team after creation. You are allowed to turn these into assistant coaches if you so choose.