National Series 2011

I thought they could be in the tournament but only if their original team had been knocked out

Yeah, I think that's correct. I think NS ruleset = LHBA ruleset?

1.2 – Substitutions.
1.2.1 – A team can substitute a player in response to player injury or unforeseen absence.
1.2.2 – If the player injury occurs more than two weeks prior to the tournament, the substituted player must be chosen and declared before the first day of tournament play.
1.2.3 – If the injury occurs during the tournament a substitute may be chosen to replace the injured player.
1.2.4 – Once the change is made, the team is then set for the duration of the tournament.
1.2.5 – No player can play in two different teams in the same event, unless his/her team has already been eliminated