Injured hooker Thomas Leuluai will also be in the frame but Chad Townsend's confirmed departure at the end of the season to return to Sydney on compassionate grounds could see him used back in the No6 jersey.
"With the impending arrival of Issac Luke, obviously places within our squad for the hooking position is limited to more of a back-up role, and I understand Nathan's got higher ambitions," explained coach Andrew McFadden.
"So we had a discussion about what his role would be at the club if he was to stay and I understand that he's probably got bigger ambitions than that."
McFadden hinted the dummy-half support roles were yet to be confirmed and admitted more additions were likely to be made to the Warriors 2016 roster.
"At this stage Siliva is obviously still contracted to us," said McFadden.
"There is some stuff going on in the background but at this stage he is still with us for next year.
"You can probably expect some signings. I don't know about any major signings, it's more about depth and filling our squad up with the numbers we need to compete in an NRL season.
"But certainly there's a few little things we've got to tidy up. But the core of the squad along with the signings we've already made will make a significant impact for us next year."