The series begins at the SCG on Sunday and Williamson said New Zealand wanted to wait until the day of the match to assess the pitch and decide whether Ferguson would make his debut. At the very least, Williamson was impressed by what he saw - and faced - from Ferguson in the nets on Saturday.
"He sent a couple of messages at training," Williamson said. "He bowled really nicely so we'll have to wait and see. He bowls quick and runs in and bumped me a few times which was great. It's what you want to face and it's fantastic preparation. The Australians will do the same...He's a one in 14 chance, I suppose."
Whatever XI New Zealand choose, they will have no more than four of the same players who secured the trophy in the third ODI in Hamilton earlier this year: Williamson, Martin Guptill, Henry Nicholls and Matt Henry. And it is possible that Nicholls could yet miss out, with suggestions that New Zealand would give themselves ample bowling options by including both allrounders Jimmy Neesham and Colin de Grandhomme.
"We want to have another look at the surface tomorrow," Williamson said. "There's a little bit of uncertainty about what the surface might do. It has spun here in the past. It looks a good surface, it's quite hard, they might have rolled in perhaps some old grass clippings to get a little bit more grass on it, maybe to add a bit of pace."
New Zealand begin this series ranked third on the ICC's one-day international table while Australia are on top. Even if New Zealand were to win all three games they would not gain a position, though it would be enough for Australia to drop below South Africa and into second place.
"It's an enjoyable series, it always is, and they're always tough opposition and a very strong side so you don't need more motivation to get up to play your best cricket against the best in the world," Williamson said. "The focus is for us to play our best cricket and if we do that we know we can beat anyone."