In the 55-page decision on the appeal lodged by both Mexican clubs, FIFA justifies the decision on the grounds that Pachuca and Club Leon share the same owner, something that is prohibited by the competition's regulations.
Pachuca and Club Leon, who, according to the appeal committee, are both in breach, "are controlled by the same people, who exercise significant influence over their respective decision-making processes."
Club Leon were in Group D of the Club World Cup, along with Chelsea (England), Esperance (Tunisia) and Flamengo (Brazil) and their replacement will have to come from CONCACAF, although they don't have to be a Mexican club.
Last Friday, the Court of Arbitration for Sport (CAS) confirmed that it had received individual appeals from Mexican clubs Leon and Pachuca, requesting a declaration that both are eligible to take part in the Club World Cup, contradicting FIFA's decision to exclude the former.
The FIFA Appeals Committee ruled last month that both sides had violated the Competition Regulations in relation to multiple club ownership and, due to this infraction, Leon, coached by Argentinian Eduardo Berizzo and with Colombian ex-FC Porto player James Rodriguez in their squad, was excluded from the competition.
The TAD also explained that Leon had also lodged an additional appeal against the FIFA Secretary General's decision to be reinstated as a participant in the Club World Cup.