The thing about lightbox is they charge subscriptions per sports, with sky you can channel surf and realise that there isn't much on so you might as well watch the A-League, or a family could have sky for the rugby and one of the kids happens to like the A-League so they all watch it. So A-League has the potential to reach the entire sky audience (which is 1/3rd of households?). WIth lightbox you will get the Phoenix fans subscribing to the A-League but you have less chance of casuals getting interested.
If Lightbox has it then it would have to be something like Lightbox has all the A-League but they do a deal with TVNZ to play the Phoenix either live or delayed. Coliseum who makes up half of lightbox sports already has that relationship with TVNZ.
Ideally they would do it as a loss leader and give it free to all spark customers or something like that.