Sunderland have sacked head coach Tony Mowbray after 15 months in charge, the Championship club said.
The team in England’s northeast are ninth in the table but on a recent poor run of one win from their last five games.
They drew 1-1 at struggling Millwall on Saturday.
“This was a difficult decision to make but we remain loyal to our ambition and our strategy, and felt that now was the right moment to take this step,” said sporting director Kristjaan Speakman.
The 60-year-old Mowbray’s assistant Mark Venus has also left the club with coach Mike Dodds taking over in the interim.
Sunderland face arch-rivals Newcastle United in the FA Cup third round next month.
There were two managerial casualties in England’s second tier on Monday, with Swansea sacking head coach Michael Duff.
The Welsh club are 18th in the 24-team championship.
The 45-year-old Duff was only appointed in June.
“I believe it is now in the best interests of Swansea City to make a change of head coach,” Swansea chairman Andy Coleman said.