Paolo Di Canio attempted to manage Sunderland using “unprecedented levels of fear”, according to former Black Cats chairman Niall Quinn.
The Italian was fired on Sunday amid talk of widespread unhappiness within the squad about his management style.
Quinn, a former player, manager and chairman at the club, told the Sun: "Paolo's idea to rule through fear was to an incredible level. I think they were unprecedented levels of fear.
"Players weren't allowed to speak to staff - their own work colleagues. It's awful stuff.
"If I was a senior player, and I saw it coming to breaking point, I think I would have been hard-pressed not to stand up and give it back to him as well.
"It was very brave of the players to do what they did. Player power will be criticised but in this particular incident they felt they were going into battle for a leader who wasn't with them."