Charlton will today begin the search for a new manager just six months after appointing Iain Dowie as the successor to Alan Curbishley.
The club will release a statement later today, but former boss Curbishley himself has already ruled himself out of a return.
He told Sky Sports News: 'I left Charlton for a new challenge. Going back would not be good for me or for the club.'
The Addicks are currently bottom of the Barclays Premiership, winning only two of their 12 matches.
Further comment is expected later today, after a short statement was posted on the club's official website.
'The Addicks announced on Monday night that head coach Iain Dowie had left Charlton,' it read.
'The club will issue a further statement on Tuesday morning.'
Despite their terrible league form, Charlton had last week reached the last eight of the Carling Cup where they will face Wycombe.
However, the south-east London club's predicament at the foot of the Premiership proved too much, which appears to have prompted chairman Richard Murray and his fellow board members to act.
When Dowie - who agreed a three-year deal - was unveiled as the Addicks' first new manager in some 15 campaigns following the summer departure of long-serving boss Curbishley, Murray was at pains to point out the importance of retaining top-flight status given the new television deal which is set to come into force next season.
Now it seems that factor has proved critical in the decision to part company with the 41-year-old, who had wasted little time in spending the best part of £10million on new additions to the squad.
Charlton are likely to put assistant Les Reed in charge for the weekend Premiership clash at Reading.
The likes of Billy Davies, now at Derby, and Peter Taylor were among the 20 candidates interviewed for the post, before the late availability of the former Northern Ireland striker.
Dowie took up the reins at The Valley in controversial circumstances, having just left south-London rivals Crystal Palace.
He was involved in a high-profile fall-out with Eagles chairman Simon Jordan, who claimed Dowie misled him about his reasons for quitting Selhurst Park.
Dowie had a compensation clause in his contract which meant if he left for another club, they would then have to pay Palace £1million.
However, Jordan agreed to waive the clause - and this prompted the Palace chairman to take action for 'fraudulent statements about his reasons for leaving the club', with a court representative issuing Dowie with a writ at his inaugural press conference in May.
The allegations were denied by Dowie, who was promised Charlton's full backing for a court case on the dispute that is due to he heard next summer.
How Dowie's departure will affect that case remains to be seen.
Despite admitting he had no sympathy for Dowie, Jordan insisted the Addicks were wrong not to hold on to him.
'I think Charlton have not really given him a chance,' said the Palace chairman.
'Gutless, faceless people take those decisions, don't they?'
'Iain went and joined a club who were not strong enough. I am disappointed for him. Given time, he would have done well because he's a winner.'
After a playing career which took in spells at West Ham, Southampton and Palace as well as a distinguished international career with Northern Ireland, Dowie took his first steps into management at Oldham.
He led them to the Division Two play-offs in 2003, but after financial trouble hit the Lancashire club, he moved on to Palace in 2003.
The Eagles were languishing in 19th in the Championship, but a sensational run of form saw them reach the end-of-season play-offs and earn promotion to the Premiership.
It was to all end in tears, however, when Palace were relegated on a dramatic final day following a 2-2 draw at, ironically, Charlton.
Dowie guided his team to the play-offs again last season but lost in the semi-finals to Watford.