Newcastle then issued a statement on Tuesday afternoon insisting the 57-year-old had not been sacked and remains in charge.
Richard Bevan, chief executive of the League Managers' Association, revealed that Keegan had also not quit but will be holding further talks with the club's board over the next few days in an attempt to resolve the issues.
"Newcastle Football Club and its fans are massively important to Kevin," said Bevan, who spoke at length to Keegan on Tuesday evening.
"He has not resigned, he's in a difficult position and he'll be discussing important issues with the Newcastle board over the next few days," Bevan told BBC Radio 5 Live.
He added that the LMA will keep supporters, media and other stakeholders within the game fully informed of developments.
Newcastle's statement on Tuesday stated: "Newcastle United can confirm that meetings between members of the board and manager Kevin Keegan were held both yesterday (Monday) and today (Tuesday).
"Kevin has raised a number of issues and those have been discussed with him.
"The club wants to keep progressing with its long-term strategy and would like to stress that Kevin is extremely important, both now and in the future.
"Newcastle United values the effort and commitment shown by Kevin since his return to St James' Park and wants him to continue to play an instrumental role as manager of the club.
"For the avoidance of doubt, the club has not sacked Kevin Keegan as manager."
The cause of the Keegan's unhappiness appears to centre on the club's relative lack of signings in recent weeks and reports they were willing to sell Michael Owen on deadline day.
He had voiced his belief last Friday - after winger James Milner had been sold to Aston Villa for £12 million - that he would have three or four more players at his disposal by midnight on Monday.
In the event, only striker Xisco and loan signing Ignacio Gonzalez arrived on Tyneside, while troubled midfielder Joey Barton was the subject of an unsuccessful approach from another top-flight club.




