West Ham announced on Tuesday that they had sacked head coach Nuno Espírito Santo after a disappointing start to the Championship season.
The 52-year-old oversaw the Hammers' relegation from the Premier League last season.
For many, the London club were favourites for automatic promotion back to the top flight but they are currently eighth in the second-tier table, six points behind leaders Middlesbrough.
"West Ham United can confirm that men's first-team head coach Nuno Espirito Santo has left his position with immediate effect," the club said in a statement.
“Following a thorough review of the start to the EFL Championship season, the board of directors believe that a change is necessary at this time in order to ensure that the club's objectives and expectations remain on track.”