A day after Clarkson was admitted to hospital with Guillain-Barré syndrome (GBS), the Hawks have reiterated the condition was caught early and the two-time premiership coach has "responded well to initial treatment". 

But president Andrew Newbold has penned an open letter to the club's members and supporters that indicates Clarkson won't be rushed back into his role. 

"Circumstances like this certainly put the game we play into perspective," Newbold said on the club's website. 

"There is nothing more important than our health, and the health of our families and friends, and that is why our club will give 'Clarko' as long as he needs to fully recover.

"A timeline for Alastair's return to coaching is not something we are considering at this stage, and in the meantime, we have asked experienced assistant coach Brendon Bolton to step into the senior coaching role temporarily.

"As CEO Stuart Fox said, our primary concern is for Alastair's health and we want him to concentrate all his energies on recovery before he considers returning to the coaches' box."

Fremantle coach Ross Lyon said the character of Clarkson would be tested as he battles the illness.

"It's his private life. We're concerned. I have enormous respect for him. He'll get full support from Hawthorn and the footy world," Lyon said on Wednesday.

"But knowing Alastair, his character will shine through and he'll work his way through it and we'll see him coaching sooner rather than later."

The Hawks have been overwhelmed by the number of messages they have received supporting Clarkson during the sudden health crisis. 

It was lingering back pain that prompted him to seek medical attention, and the potentially dangerous GBS was diagnosed. 

In the most severe cases of the disorder, reversible paralysis can spread to all four limbs plus the patient's trunk. 

Treatment is effective but can take time, with the patient usually needing extensive physiotherapy to return their body to its previous state. 

Newbold reiterated Clarkson had been "very fortunate" in the early diagnosis of his condition and was in "good spirits". 

"Alastair is under the care of very experienced specialists and is in the best place to receive treatment for what is a rare condition," he said.

"I'd like to make special mention of the doctors who are treating him and wish them good luck keeping Alastair in his hospital bed!"

Bolton will coach the team this week against Greater Western Sydney on Sunday and for the foreseeable future. 

Newbold said it would be "business as usual" with Bolton – Clarkson's assistant for four years after two as Box Hill's senior coach – and backed him to do a "fantastic job". 

"Brendon shares similar coaching philosophies to Alastair, and was a teacher prior to his move into full-time football coaching," he said. 

"Anyone who has had the pleasure of meeting 'Bolts' will no doubt be able to tell you what an outstanding communicator, engaging teacher and passionate coach he is. 

"While I am certain Brendon's transition will be seamless, we can all take confidence knowing he will receive a great deal of support from our outstanding assistant and development coaches, leadership group, players and administration staff in Clarko's absence. 

"As is always the case at Hawthorn, it will be a team effort.

"As Alastair often says, 'You lose a soldier and you replace him with another one', and while we see this as a big challenge for our club, I can assure you it is one we confront head on."