Wigan owner Dave Whelan has accused Mike Ashley of being "greedy" as he reportedly holds out for a buyer who will pay £250million for Newcastle.
Whelan also believes Ashley underestimated the magnitude of what he was taking on when he bought the Magpies in July 2007.
Ashley put the club up for sale after the backlash following Kevin Keegan's abrupt departure in September, with investment bank Seymour Pierce, who have been tasked with finding a buyer, revealing there were two "very serious contenders" but as yet nothing has materialised.
Whelan believes his Newcastle counterpart is being unrealistic, telling The Times: "If Mike Ashley will sell it for the right money, he will sell it next week. Now, is he being greedy? Yes."
He continued: "I don't think he has thought things through and I don't think he really appreciated just how passionate people are up there about their football.
"It is very difficult for someone who is not a Geordie to run that football club and I said to Mike Ashley: 'You are better off just getting your money back and stepping away.'
"You can't sack Kevin Keegan and expect the fans to get behind you. He will never be able to repair the damage between himself and the fans. Do that and you are down the pan. I told him, 'You're gone.'"
Wigan boss Steve Bruce led his side to a last-gasp 2-2 draw at St James' Park on Saturday and he has been linked with a return to his native north-east.
Whelan, though, poured scorn on such a possibility.
"He won't come here and work with Mike Ashley," Whelan added. "Steve wants to work with a chairman who understands the game and does not expect too much, too soon. There is no chance he would go near a football club if it is not run the way he thinks it should be."
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