Gunston had been sidelined since late May with a foot problem. While the All-Australian forward will make a welcome return, the Hawks lost Karl Amon to persistent knee soreness and Ned Reeves to a new knee injury.
Nick Watson was already confirmed as being sidelined with a hamstring issue, while Calsher Dear was dropped.
Noah Mraz and Matt Hill will make their AFL debuts, with Will McCabe the other addition.
Coach Sam Mitchell was cautiously optimistic before Thursday training about Gunston, but noted it was not the first time he had talked about the chances of his return.
The All-Australian forward came back from the mid-foot injury for the round-13 win over St Kilda. Gunston had kicked five goals when he went off for the last quarter, with the Hawks initially saying he was being rested.
He has been out of action since that game.
"We're much more optimistic - having said that, I've stood here probably three times over the last six weeks and said 'looking better'," Mitchell said.
"So I will say the same thing again - looking better."
The Hawks coach said a decision last week to ease off Gunston's training appeared to have helped.
"Let's take the extra bit of time, and that seems to have made a positive impact," he said.
Mitchell also thinks Watson will only miss Saturday's Launceston game against the Demons.
"He's overloaded in his hamstring, which means the risk of further damage is there. We don't want to take that (risk) at this time of year with a player like him," Mitchell said.
Watson's absence has opened the way for rugby league convert Hill to make his AFL debut.
"There were some things from rugby that he brought straight away," Mitchell said of Hill.
"If he's on the mark, I wouldn't suggest you try to take him on. Tackling him, I'd be a little bit careful too, because he has a few tricks up his sleeve."
Mitchell was also optimistic that the Hawks are making progress on a new deal for forward Mitch Lewis, who has played 15 games this season.
But Conor Nash remains sidelined with a neck problem - he last played in round 12 - and Mitchell said they hoped to have more news next week about when he might return.
Hawthorn had their worst loss of the season to Melbourne in round 11 at the MCG and they will host them on Saturday in Launceston.
It is a massive game, with the Hawks third on the ladder and the Demons seventh.
"Melbourne early in the year, everyone was watching them, not sure. I think everyone is sure now - they're a good side," Mitchell said.
"They have potency with a lot of their individual players, but also their system.
"The way they play is conducive to strong, high-level footy in big games and big moments. We weren't able to get it done last time.
"We weren't even close to their level of intensity around the ball, in particular. We learned some lessons from that game."
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