New Hawthorn skipper Jarryd Roughead says it's difficult to know what Essendon will bring to their round-one AFL clash, but his own team's list changes also make them an unknown quantity.
The traditional rivals will meet in round one on Saturday night at the MCG, with the Bombers welcoming back a host of players from year-long doping bans.
Roughead says it's difficult to plan for Essendon with their players returning and the Bombers not fielding a full-strength line-up during the pre-season.
"That's a bit of the unknown," the key forward said.
"These guys have played a few pre-season games but, obviously, haven't had their full side in - Cale Hooker only played VFL on Friday night.
"You can prepare as best as you can but, until you know that 22 up until an hour before the game, you really are just guessing at the moment."
It's also difficult to predict how the high-flying Hawks will fare in the opening round, with veterans including Sam Mitchell and Jordan Lewis no longer at the club and former skipper Luke Hodge banned for a match after missing a training session without notice.
They have recruited Sydney's Tom Mitchell and former Gold Coast player Jaegar O'Meara.
Roughead missed last season as he battled skin cancer but the time out hasn't dulled his competitive edge.
He bristled on Tuesday at a question about the Hawks' predicted fall down the competition ladder after finishing fifth last season following three successive premierships.
"I don't think we're expecting (that)," he said.
"Both sides are a little unknown because we've got new players as well."
He did concede the Hawks hadn't been at their best through the pre-season competition but felt they'd rise to the occasion of a big MCG crowd.
Roughead, 30, said he was trying to keep a lid on the hype around his return.
"I've been building towards this; I've played three pre-season games and feel pretty good.
"There's a bit of hype around it but it's still a footy game so I'm not getting over the top."