Before announcing their final squad for the tournament, teams were required to name a preliminary squad of 30 players by 11 May 2010, 30 days before the start of the tournament. With the exception of those involved in the 2010 UEFA Champions League Final, the players listed in the preliminary squad were then subjected to a mandatory rest period from 17 to 23 May 2010. The preliminary squad would then have to be cut to a final 23 by 1 June 2010 (midnight CET). Replacement of seriously injured players is permitted until 24 hours before the team in question's first World Cup game, though replacement players do not have to be drawn from the preliminary squad.