Having guided the Bluebirds to a 12th-placed finish in the Championship in 2023-24, there was optimism that further improvement could be made this season.
However, after six games, Cardiff sit bottom of the standings with just one goal and one point to their name.
The latest of five defeats came at the hands of Leeds United on Saturday afternoon, the Welsh outfit going down by a 2-0 scoreline having not been helped by a first-half sending off.
Despite that result needing to be put into context, Cardiff's hierarchy have decided to part ways with the Turkish manager.
Bulut leaves the Cardiff City Stadium having recorded 21 wins, seven draws and 30 defeats during his 15-month stint.
Brief statement from Cardiff
In a statement, Cardiff said: "The board of directors wish to thank Erol for all of his hard work and wish him well for the future.
"First team Coach Nikolaos Karydas will also depart and leaves with the Club's best wishes. Further backroom staff confirmation will follow in due course.
"Omer Riza will take charge of the First Team on an interim basis, while the club look to recruit a new permanent First Team Manager."
What next for Cardiff?
Cardiff now have a full week before they square off against Hull City at the KCOM Stadium next weekend.
With games against Millwall and Bristol City to come in quick succession before the international break, a decision must be made over whether to place faith in Riza or move for an outside candidate.
Riza has not managed at senior level since 2017 when he was in charge of a Leyton Orient side that were relegated to the National League.
Since then, though, the 44-year-old has spent time coaching Watford's academy sides, as well as being a coach in the England Under-16s and Under-17s setup.