Sunderland defender Titus Bramble has warned boss Paolo Di Canio the dressing room will revolt if he continues to put himself above the players.
Di Canio was the surprise appointment to replace Martin O'Neill in March and succeeded in keeping the Black Cats in the Premier League but Bramble, who is one of several squad members to run into conflict with the Italian, believes he has already made big mistakes during his short time in charge.
The 31-year-old was fined two weeks' wages for missing a weights session - a punishment he intends to fight with the help of the Professional Footballers' Association.
Bramble will leave Wearside when his contract expires in June and has lifted the lid on Di Canio's autocratic management style, saying the 44-year-old risks alienating the dressing room if he does not change.
"I've never played under anyone like him and I've played for some of the best managers around," Bramble told the Telegraph.
"Steve Bruce, Roberto Martínez and Sir Bobby Robson. He thinks he knows everything, but he has got a lot to learn. He's got a long, long way to go before he gets anywhere near as good as Sir Bobby Robson.
"He's a young manager trying to stamp his mark on things, but he's making some big mistakes. He's targeted the easy players, the ones who are leaving anyway, trying to show he's the boss.
"I was fined for not going to a weights session. Everyone else at the club thought it was ridiculous, but he's trying to be tough. The fines he has tried to dish out are way too harsh.
"I've been told by the PFA he did exactly the same thing at Swindon and they fought him then too. He was fine at first, but he's a strange person.
"We all remember what he did as a player, shoving a referee over. He was no angel and players know that. Then he comes in and starts trying to make out he's an angel and does everything perfectly.
"There are a lot of strong characters in that Sunderland dressing room and he is upsetting them. It isn't just those who are leaving."
Bramble also believes Di Canio is more concerned with building his reputation in the media than building bridges with his players.
"He comes out in the media and hammers players and he hasn't said a word to them," Bramble added.
"Imagine how Connor Wickham felt when he was told by his family what the manager had said about him [being too worried about how he looks] in the press. He's never said anything like that to his face.
"He's 19 and the manager is battering him in the media. Fine, say that behind closed doors, keep it in house. Managers have a go at players all the time, but in the dressing room or in their office.
"You don't see the top managers behaving like he does.
"He seems to be more worried about his image outside of the club, sounding good in the media, than anything else. It's a dangerous game to play."