I'd imagine Lia will get the Bertos treatment and get offered something new at a much reduced rates (bertos reporting went from 250K to 90K - although not sure how accurate) and become a squad player. Not the worst option to have as cover.
See I have a problem with guys who were first teamers playing backup because inevitably the only way they can go is down (and I'm assuming that Lia won't be first choice by next season, I think he could actually lose his spot by the end of this season actually).
Without removing all experience from the squad I see that role for younger players who can improve and get experience. In central midfield we'll have both Rufer and Ridenton who'll be a year older and into year 2 of a three year deal, both will really start to need minutes and if you keep guys like Lia around that's just another block for them.
If we're truly serious about our academy and bringing kiwi youngsters through, and I personally think that a proper academy developing players is the only way in the long run that we'll compete at the top level, then you can't have guys like Lia, Bertos etc blocking the pathway for the younger guys