The bright colours of their footwear will be in stark contrast to how pale their faces turn when the combustible character walks in the door.
The good life will be over. Paradise could become hell.
All of the above is true - IF you believe the majority of what is being discussed among the club's supporters.
Keane's reputation as a strict disciplinarian able to cause grown men to wilt simply be fixing them with his cold, steely stare has been earned over decades as a player and a manager.
He certainly does not lose many arguments, and backs down from even fewer.
But, behind the iconic image as one of the toughest men the game has ever known, there is is a truth which many players who have stood alongside him on the pitch or worked under since he moved into management are only too happy to reveal, even if it is likely to be to the Cork man's chagrin.
No one can be Mr Angry all the time, or his voice simply ceases to be heard.
Likewise, if you try to rule by fear, eventually you will paralyse the very ability you are trying to coax out of the men under your charge.
That's not to try and suggest Keane is really a big softy who just presents a tough-guy image.
Of course he is not a man to be crossed, who demands and commands respect, and who will not leave anyone in any doubt exactly what it is he expects of them.
But if he is to be the next manager of Celtic, is it really going to mean the sea-change that is being suggested?
To answer in the affirmative would be to grossly underestimate how tight a grip Neil Lennon had on his players.
Sure, the man who has just vacated the hot seat does not have the confrontational personality carried like a life mission statement by Keane.
But Lennon was no shrinking violet, as his infamous head- to-head with Ally McCoist on the touchline at Celtic Park confirmed, along with his run ins with match officials when he felt he or is team were being wronged, especially in the first few years of his managerial apprenticeship.
Away from the public glare, Lennon was a much more amiable individual, using his intelligence to pre-empt situations or win the argument if one could not be avoided.
His players could enjoy a laugh and a joke with him, as they did with coach Garry Parker and even with his assistant, the more-intense Johan Mjallby.
But, no one was left in any doubt where the line was or how close they could get to it before Lennon came down on them like a ton of bricks.
Anthony Stokes - who has previous with Keane at Sunderland where the rookie boss dropped the striker, plus Tobias Hysen and Marton Fulop after they were late for the team bus ahead of a game at Barnsely, and transfer-listed Liam Miller for repeated poor time keeping - is sure to be sounded out by his team-mates about what to expect if the man currently acting as assistant to Martin O'Neill with the Republic of Ireland does get the job.
The striker is likely to tell them the more things change, the more they will be staying the same, because Lennon did not exactly allow him to break the rules without paying the consequences - usually in pounds.
Stokes' tardiness was a particular bug-bear, and swelled the fine fund regularly and significantly.
But Lennon was also the first to stand by his players when they needed his support, as he did with Leigh Griffiths when he became embroiled in 'Sing-gate'.
The new Bhoy was hammered with a fine for being stupid enough to sing about Hearts going bust in a pub in Edinburgh.
When a second allegation of indulging in a song about Rudi Skacel led to much more serious charges from the SFA - the case will finally be brought before them on Thursday, while the outcome of a police investigation has still be announced - Lennon refused to bow to fan pressure to drop the player or even sack him.
Stokes was also appreciative of Lennon's refusal to indulge in a knee-jerk reactions when he was trying to secure a new contract against a background of a police investigation into an alleged assault on an Elvis impersonator in Dublin - a case which is going to court.
Quite how Keane would react if anyone broke his or club rules is, like the appointment of the new manager itself, conjecture.
It's a safe bet there will not be a queue of players willing to become the first to find out.
But if he does succeed Lennon, the Celtic dressing room won't change radically.
He will inherit a group of players happy at their work, but aware they are there to work and under whichever rules the new gaffer dictates, just as they did with Lennon.