Wigan Athletic have sacked manager Leam Richardson after they lost six of their past seven games to fall into the Championship relegation zone.
The 42-year-old led the Latics to the League One title last season in his first full season in charge.
Richardson, who had only signed a new three-year deal on 25 October, initially joined the club as assistant to Paul Cook in the summer of 2017.
Assistant Rob Kelly has been placed in caretaker charge.
Richardson took over on a temporary basis in November 2020 after John Sheridan left with the club in administration and struggling at the bottom of League One.
He guided the club to safety with a strong finish to the season and new owners Phoenix 2021 Limited appointed him on a permanent basis in April 2021.
They missed two chances to seal automatic promotion last season before ultimately claiming the title on the final day with a 3-0 victory over Shrewsbury.
A win over Blackburn on 12 October moved them to within two points of the Championship play-offs places this season but they have taken just one point from the subsequent seven matches and lost 2-0 at Coventry on Tuesday.
They are two points behind 21st-placed Blackpool, who visit the DW Stadium on Saturday.
Wigan thank ‘much-loved’ Richardson
Richardson’s most vital involvement last season came away from the pitch.
He was credited with helping to save the life of striker Charlie Wyke in November after he had a cardiac arrest in training – beginning cardiopulmonary resuscitation (CPR) process before club doctor Jonathan Tobin took over.
The Latics said in a statement that the former Accrington boss would “always be held in high regard by fans”.
“Leam will be fondly remembered as one of the most significant managers in the club’s 90-year history,” they said.
“However, having looked at the recent run of form that is challenging the team’s status as a Championship club, the board have made the decision to make a change.
“The club would like to place on record it’s thanks to Leam for his efforts and dedication throughout his time at the football club, none more so than during the period of administration and his instinctive reaction that helped save the life of Charlie Wyke.
“A much-loved individual and someone who Latics fans will always hold in very high regard, Leam will always be welcomed back at the DW.”
Analysis – ‘What next after bold move?’
Mike Minay – BBC Radio Manchester sport reporter
This is a bold move by the owner who just 16 days ago appeared to back the manager who kept the club in League One during a year of administration before winning promotion the season after.
Leam Richardson had moulded the squad in his vision and had a group of players that knew him and his style. Now it’s down to someone else to take over the task, get to know that squad and get them out of the relegation fight.
Who could replace him? A quick scan through the managerial market – you have a young manager such as Rob Edwards who was given a short opportunity by Watford recently. Dean Holden lives in the local area and has experience at Championship level with Bristol City.
There’d be some bigger names that might be tempted – Steve Bruce to his former club maybe? Although his recent stint at this level didn’t go well with West Brom.