I found this...
http://resources.fifa.com/mm/docume...regulationsfwcbrazil2014_update_e_neutral.pdf
6. A player listed on the final list may only be replaced in the event of
serious injury up until 24 hours before the kick-off of his team’s fi rst match.
The replacement players do not need to be limited to the release list. Such
replacements must be approved in writing by the FIFA Medical Committee
upon receipt and acceptance of a detailed medical assessment in one of the
four offi cial FIFA languages. The FIFA Medical Committee shall approve the
request if the injury is suffi ciently serious to prevent the player from taking part
in the competition. The participating member association shall inform FIFA
accordingly of the player’s full details (cf. par. 4 herein) at the same time as
when submitting the request to replace the injured player.
7. All 23 players shall be named on each start list (11 selected players and 12
substitutes). Up to a maximum of three of the substitutes may take the place of
the selected players at any time during the match.
8. Not more than 23 people (11 offi cials and 12 substitutes) shall be allowed to
sit on the substitutes’ bench.
9. Before the start of the fi nal competition, all listed players must prove their
identity, nationality and age by producing their legally valid individual passport
with photograph (stating day, month and year of birth). Any player who fails to
submit his passport shall not be allowed to take part in the fi nal competition.
10. To protect players from burn-out before the fi nal competition of the 2014
FIFA World Cup™, FIFA has set dates as follows:
(i) The fi nal matchday at club level for the 30 players nominated on the
release lists for the fi nal competition of the 2014 FIFA World Cup™ is
18 May 2014.