can't sign until the next transfer window. He'd probably want to pick up another gig (MLS) by then.
seems like there is some leeway to signing players without a club
1. Players may only be registered during one of the two annual registration periods fi xed by the relevant association. As an exception to this rule, a professional whose contract has expired prior to the end of a registration period may be registered outside that registration period. Associations are authorised to register such professionals provided due consideration is given to the sporting integrity of the relevant
http://resources.fifa.com/mm/document/affederation...
One thing that NZF stuff ups have resulted in, casual fans having a better understanding of FIFA statues