History for andrewvoerman

NZFA

Unsure about this, mutual termination makes him a free agent, which now allows him to talk to any club, at any point. 

Hence why A-league can sign people whenever, as most of the peeps they sign are out of contract players (hence the no transfer fees)

Transfer windows are for contracted players.

He can talk to clubs, he can even sign with them, as NelFoos points out, but he can only be registered to play for clubs in places that had windows open when he was released (or once new windows open, ie in England, in January). The A-League examples you're referring to fall under the third sentence in the following, from Fifa.

"Players may only be registered during one of the two annual registration
periods fixed by the relevant association. Associations may fix different
registration periods for their male and female competitions. 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."

Edit: Oops, I see I was slow while I went citing Fifa.