Lee Bowyer is set to leave Charlton after the club revealed they have failed to agree terms with their manager over a new contract.
The former Leeds and Newcastle midfielder, capped once by England, returned to the club where he started his playing career and, in his first full season at the helm, led the Addicks to promotion to the Sky Bet Championship.
But Charlton, who overcame Sunderland in the League One play-off final last month, are up for sale and current owner Roland Duchatelet is unwilling to offer Bowyer anything longer than a 12-month extension.
A statement on the club website read: "Lee has been offered a one-year extension to his contract at a level which is approximately three times what he had since his last increase when he became permanent manager in September.
"This reflects the strong desire we have to continue to have Lee as our manager. But Lee wanted much more.
"It is fair that Lee feels he should be paid like many other Championship managers. That the average Championship club makes a loss of around £15million per year is not something players should care about. The owners are crazy.
"This is why we could not come to an agreement.
"The fact the club is for sale has not helped with finding an agreement. The current owner needs to take into account that a new owner may want to appoint his own manager."
With manager and club at an impasse, Charlton intend to appoint a caretaker soon though they appear not to have given up hope of reaching a resolution.
The statement added: "The club hasn't started to look for any other manager in the meantime and does not intend to appoint a permanent manager, since the club is going to be sold.
"A caretaker manager will be announced in due course and in the meantime the other staff members will continue to prepare the upcoming season for which a lot of good work has been performed already.
"If Lee does change his mind before his contract expires and chooses to continue his good work at Charlton, he is still welcome to stay.
"However our ability to sell the club is the most important thing right now."
Earlier in the day the club completed the signing of striker Macauley Bonne from Leyton Orient for an undisclosed fee.
Zimbabwe international Bonne has agreed a three-year deal to become the Addicks' first signing since winning promotion to the Sky Bet Championship.
The 23-year-old hit 23 Vanarama National League goals last season as Orient won promotion to League Two as champions.
"I'm delighted to be here now, it's been something that's been on the cards for a while now and so I'm delighted that it's over the line," he told the club's website.
"I thought it was the best move for me to progress and become a better player."
Bowyer said: "We have to get people in that are going to do things in the attacking third, that's what we're focusing on and what we've been focusing on for a long time.
"It's been something that we've been keeping an eye on and now it's the right time for him to come to us."