No reason he can't sign from the UK.
Read this: http://www.melbournevictory.net/forum/showthread.php?57908-Victory-sign-Isaka-Cernak
and then this: http://www.melbournevictory.net/forum/showthread.php?57908-Victory-sign-Isaka-Cernak/page21
Pretty big fall from grace in the fans eyes, hopefully the potential that he had on page 1 is realised if he signs with us.