VERY few people can tell Ash Hansen what to expect on Thursday night.

That's because very few people, at least in the competition's recent history, have ever been parachuted into a senior AFL coaching role for one game – and one game only.

Hansen will act as Carlton's interim stand-in coach for its round two clash against the Western Bulldogs, after Michael Voss – fresh from leading the side to victory in his first match in charge – entered the AFL's health and safety protocols last Friday.

It's a task Hansen, himself described by insiders as a senior-coach-in-waiting, will surely relish. It comes after a successful nine-year apprenticeship as an assistant at the Bulldogs, followed by a role at the Blues won last October. The fact his first coaching appearance will come against his former side was described by Hansen this week as "Shakespearian irony".

The last instance of a fill-in, one-game coach occurred in 2018 when Jaymie Graham stepped into the hot seat for West Coast when Adam Simpson took leave for an illness in the family. Coincidentally, Graham also did so against the Western Bulldogs and masterminded a 51-point victory for the Eagles.

Before forging his own coaching career at Fremantle, Chris Connolly also famously took charge for one game only while at Hawthorn when Peter Schwab fell ill the night before a game in 2001. That game being when Ben Dixon kicked a goal after the siren to defeat Carlton at the MCG.

Then there was Gary O'Donnell, who stepped in for Kevin Sheedy in 2006 following a truly bizarre set of circumstances.

The former playing legend, who won the Bombers' best and fairest in their 1993 premiership season, was asked to fill in for Sheedy after the veteran coach was cleaned up by Dean Solomon during a training session earlier in the week.

Such was the brutal nature of the blow from one of his own players, Sheedy was forced to undergo a complete shoulder reconstruction that would leave him unable to coach the side for its upcoming clash with Carlton.

O'Donnell was immediately approached by former Bombers chief executive Peter Jackson in the aftermath of Sheedy's collision and asked to step in as a one-game interim coach. Much like Hansen has done ahead of the Blues' clash with the Dogs at Marvel Stadium, O'Donnell then had the entire week to prepare his team.

"He was having the surgery later on in the week, but Peter Jackson was thinking he'd be off with the fairies given he was coming off an anaesthetic," O'Donnell told AFL.com.au this week.

"We hadn't won for 13 or 14 straight games either, so it was a bit of a circuit-breaker as well. It was myself and all of the assistants … there was Gary Ayres, maybe Matthew Knights, Dean Wallis and I think Scott Camporeale.

"It was a collective effort, but it was just the players being able to hear a different set of voices. We did things a little bit differently than what 'Sheeds' had been doing. It was refreshing for some players."

Essendon ultimately snapped its 14-match losing run under O'Donnell, drawing against fellow strugglers Carlton. But he did things his way, and the players appreciated the subtle changes. Well, almost all of them did.

O'Donnell had decided to shift Ricky Dyson into the backline for that particular match, tasking him with the role of quelling second-year forward Eddie Betts. For the most part, he did so relatively effectively.

But, with Essendon leading by 12 points with little more than three minutes remaining, Betts kicked two goals in barely two minutes to draw the sides level and ensure that both teams walked away unhappy.

"We were a couple of goals up with a few minutes to go," O'Donnell said.

"We were a bit stodgy down back, so I moved Ricky Dyson into half-back just to get some flow going because he's not a bad ball user. I just wanted to solidify us down there, but his man Eddie Betts kicked a couple of goals to bring it back to even."

Earlier this year, Hansen took media duties in place of Voss after the side's unofficial practice match victory over St Kilda. Similarly, the game against Carlton wasn't the first time O'Donnell had been asked to fill in minor duties for his senior coach.

While an assistant under Leigh Matthews at Brisbane in the early 2000s, O'Donnell had been asked to look after the group for a pre-season match when the legendary coach couldn't make it to Sydney until half-time due to his daughter's wedding.

However, unlike O'Donnell back in 2006, Hansen won't have his senior coach watching his every move. While Sheedy was incapable of coaching the side for their clash against the Blues, he did sit in the coaches' box and observe every move his group of assistants were making.

"From memory, he was prepared to just sit on the side," O'Donnell said.

"Because the mandate was given to us as a group, he was prepared to just sit there. It probably allowed him to observe the game from another angle as well. He observed everyone else working together. But he virtually said nothing. He just sat there."

And, unlike O'Donnell in 2006, Hansen won't be asked to do things his way. Instead, the one-game Essendon coach believes the upcoming one-game Carlton coach will follow the instructions set by Voss throughout pre-season.

"It'll be exactly as they've been doing," O'Donnell said.

"They'd be mad to change anything. It'll be exactly as what Michael Voss has been doing, just to try and maintain the momentum they've built up and the things they've concentrated on over the summer.

"I would've thought Ash Hansen is the main guy, but collectively you have a group that will carry that load."