Sir Alex Ferguson has set the example of how to deal with a player acting out of line, with Eddie Howe facing a difficult issue with Alexander Isak at Newcastle.
The Swede wants out at Newcastle as he dreams of a move to Premier League champions Liverpool, who had a £110 million bid instantly rejected.
Isak was absent from Newcastle's pre-season tour and not part of first-team training ahead of the return of the Premier League as the saga drags on.
While the club are adamant their talisman is not for sale, Isak has taken drastic action to try and force the move - with The Athletic's David Ornstein reporting that the former Real Sociedad man has "no desire to reintegrate into the squad" and feels as though he has played his last game for Newcastle.
The North East out have struggled to sign a new attacker, missing out on Hugo Ekitike and Benjamin Sesko as well as being frustrated in efforts to bring in the likes of Yoane Wissa and Samu Aghehowa.
The whole situation has put Howe in a tricky situation as the manager and spokesperson but the blueprint has been set by Manchester United legend Ferguson, who never let any player act as though they were bigger than the club.
He had it written into his contract that no player should earn more than him but he also came down hard on Paul Scholes for refusing to play in a League Cup game against Arsenal - fining him two weeks' wages and making the England legend feel as though his time was done.
Sir Alex Ferguson provided the blueprint with his Paul Scholes punishment. Image: Getty A furious Scholes decided he wasn't going to play after being overlooked against Liverpool.
"We were meeting at Stockport that night at the train station," Scholes said on The Overlap.
"I actually drove to the train station and told him I wasn’t going. It was crazy, stupid, but my head had gone. After that game, it was an international break, so it went on and on, and on.
“It didn’t carry on but he fined me a weeks’ wages. There was no contact because I was with England, so I had to wait 10 days before I spoke to him. He didn’t get mad but he just fined me two weeks’ wages. I apologised but I didn’t think I would survive after that to be honest. I thought I would be gone, yes.”
Sir Alex Ferguson's incident with Ruud van Nistelrooy
There was also the situation with Ruud van Nistelrooy, who was incensed that he was not brought on in the League Cup final win over Wigan in 2006.
Ferguson brought on new signings Patrice Evra and Nemanja Vidic but Van Nistelrooy did not take kindly to the decision and insulted Ferguson in a moment of "blind range" which he lived to regret.
“It was very harsh, both ways,” Van Nistelrooy, briefly United's interim manager last term, recalled.
“Especially after five years of having such a strong bond. I learned so much from him, and in all modesty: he from me too. And yet the end was ruthless.”
The Dutchman added: “It was me who took the first step to make it okay again. I called him.
“A few times a year I felt bad about what I had done to him and the names I called him when he kept me on the bench the entire match in the League Cup final in Cardiff.
“In a blind rage, I shouted at him.”
Van Nistelrooy, who Ferguson devoted a chapter of his second autobiography to, left for Real Madrid that summer.
But United kept rolling on with the likes of Wayne Rooney, Cristiano Ronaldo and Carlos Tevez.
They were crowned European champions against in 2008 and won three Premier League titles in a row after Van Nistelrooy's exit.
Newcastle kick off the new season against Aston Villa on Saturday but Isak is almost certain to miss out. The Magpies' only additions this summer have been the £55 million capture of Anthony Elanga and the loan signing of Aaron Ramsdale.