Hawthorn admit they have no idea how long they will be without two-time AFL premiership coach Alastair Clarkson.

The architect of the Hawks’ current dynasty was admitted to hospital on Monday night with acute back pain and was diagnosed with the serious condition Guillain-Barre syndrome.

Doctors have told the Hawks that Clarkson’s prognosis is good, with the diagnosis made early.

The 2008 and reigning premiership coach has responded well to initial treatment.

But Hawks chief executive Stuart Fox is predicting it will be several weeks before Clarkson is back in charge and they have appointed assistant Brendon Bolton as the interim senior coach.

“I suspect it’s going to be at least a few weeks, but maybe longer,” Fox said.

“It is a serious condition, but the good news is we’ve detected it early.

“Our expert medical advice suggests he will make a full recovery.”

Fox added Clarkson had complained of back pain for several weeks, but the former AFL defender thought it was related to an old playing injury.

“That pain has become quite severe yesterday,” Fox said.

The syndrome involves inflammation of nerves around the spinal cord.

Bolton has been an assistant at Hawthorn for six years.

He was appointed as interim coach ahead of former Carlton coach Brett Ratten, the only member of Hawthorn’s coaching staff with senior AFL experience.

Captain Luke Hodge said Clarkson and Bolton had very similar approaches to coaching.

“It’s obviously different not having Clarko there, but the messages and how we’re going to play are still going to be exactly the same,” Hodge said.

Clarkson’s illness is the newest and most serious setback to hit Hawthorn this month.

Since they mauled St Kilda on May 3 by 145 points, their rock-solid premiership defence has become shaky with two losses and a string of player injuries.

“I don’t see it as a setback – I’m sure the world will see it as a setback,” Fox said.

“The football world, it’s about being presented with challenges on day-to-day basis.

“We see it as just another challenge.”

It is 13 years since then-Hawks coach Peter Schwab had to miss a game late in the season because of a heart condition.

While Clarkson has a serious medical condition, his passion for coaching and a legendary short fuse mean there is a lighter side to the crisis.

Fox and Hodge conceded it will be a challenge for anyone to make Clarkson rest.

“I’ve already had a few texts this afternoon,” Hodge revealed.

Asked how Clarkson would be in hospital if the Hawks kept losing, Hodge said: “I fear for anyone in arm’s length.

“He’s not the kind of person who’d sit back in a bed anyway – but especially if we’re not playing great football.”

Fox said Clarkson was feeling better now that he has had treatment, but also expects hospital to be difficult for the coach.

“You can imagine trying to hold Alastair down in a bed, in a hospital – that’s going to be challenging for him,” Fox said.

“He’ll need to deal with that with his family.”

Bolton’s first match in charge will be against Greater Western Sydney at the MCG on Sunday.