Hawthorn has ruled Will Day out of its Round 1 clash against Essendon, with the club still waiting for his return date from injury to be clearer.

Day discovered a stress fracture in his foot after the Hawks' first training session back from their break in January, with the club immediately saying it would take a cautious approach with his recovery.

Last year's best and fairest winner remains in a moonboot, with coach Sam Mitchell saying the star midfielder would not be ready to face the Bombers on March 16.

"He'll miss the start of the season. How far into it that is I'm not exactly sure, but he certainly won't be available for round one unfortunately," he told AFL.com.au.

"He's been helping the coaches, he's got a great footy mind and a great understanding of the game and (we've) used him taking some meetings with the midfield, but also with our academy and younger guys to help impart his knowledge and game understanding on some of our youth.

"So he's still having an impact, but unfortunately it will be a little while until he has that impact on the field."

Mitchell said it was "too early" to know if the 22-year-old could miss up to the first month of the season.

"He's still in the boot at the moment and we know he's been ruled out of round one. He's saying 'OK, round one, so can I play round two?' But it's one of those injuries where you scan them every couple of weeks and see how much development he's had. So at the moment he's out of round one but not sure how long at this stage," he said.

Heading into his third season as coach, Mitchell said the Hawks wouldn't try to replace Day directly for however long his absence is, with a bunch of young midfielders training well in a bid for spots through the middle of the ground.

"Whether that initial opportunity is for Josh Ward, who's played a bit of wing, bit of on-ball, Cam Mackenzie spent his first year learning his craft, Henry Hustwaite has taken a whole other step, Cooper Stephens has had some good moments across the pre-season and Connor Macdonald, Dylan Moore have spent some time there," he said.

"As far as one player playing the Will Day role, it's more unlikely. I think it will be shared around. We're going to need to find some more flexible ways to move the team because he was an important part of our flexibility last season."

Day and veteran forward Chad Wingard (achilles) are the only Hawks confirmed to be unavailable for the Hawks' season opener, with Seamus Mitchell (jaw) and Bailey Macdonald (leg) others who could still be ready for the start to the season.

"We haven't played anyone competitively, we're in a reasonably healthy position and you always have a couple of players who are carrying a couple of things. You go and watch any training session at any club and I can't imagine they've got their whole squad out there so we always have a few who are on light duties for a day or a week," he said.

"Both of those guys (Mitchell and Macdonald) will be more touch and go for round one, but haven't been ruled out at this stage."