Barcelona risk not being able to register Lionel Messi or new competitions Sergio Aguero, Memphis Depay and Eric Garcia until January if they can not manage their finances and fall in line with La Liga's strict wage rules before the 31 August transfer deadline.Messi is officially considered a free agent as his previous contract expired on June 30. He is believed to have reached an agreement on a new five-year deal, including a 50% pay cut on his previous deal, but it will not be signed and registered until the budget is…