Rosenior had been handed a five and a half year contract after joining from French side Strasbourg, another club under the ownership of Chelsea co-owners Todd Boehly and Clearlake Capital. Despite the long-term vision behind his appointment, results quickly deteriorated.
Across all competitions, Rosenior managed 11 wins in 23 matches. However, a heavy 3-0 defeat to Brighton proved to be the turning point. That loss marked Chelsea's fifth consecutive Premier League match without scoring, their worst run of scoreless league games since 1912.
Following the Brighton defeat, Rosenior described his team's performance as "indefensible" and "unacceptable", while also facing visible frustration from travelling supporters. The result left Chelsea seventh in the Premier League table, seven points behind Liverpool in the final Champions League qualification spot.
In an official statement, Chelsea acknowledged Rosenior's professionalism since his arrival but said recent performances had fallen below expectations. The club added that the decision was not taken lightly, but insisted there was still a lot to play for this season.
Attention has already turned to possible replacements, with Bournemouth manager Andoni Iraola, Fulham head coach Marco Silva, and former Borussia Dortmund boss Edin Terzic all linked to the role. Iraola recently confirmed he will leave Bournemouth at the end of the season, while Silva's contract situation at Fulham remains uncertain. Terzic has also previously been considered for top Premier League roles.
Assistant coach Calum McFarlane has been appointed interim manager until the end of the season. He previously stepped in after Enzo Maresca's dismissal and oversaw a draw against Manchester City and a defeat to Fulham in January. His first match in permanent interim charge will be a high-stakes FA Cup semi-final against Leeds at Wembley.
Chelsea also said the club will undergo a process of reflection to ensure a stronger long-term appointment is made. Rosenior's time in charge included five Premier League wins in 13 matches and a run of four FA Cup victories, all against lower-league opposition, which took Chelsea to the semi-finals.
Statistically, Chelsea's form under Rosenior was poor. The club lost five straight league matches without scoring, went 12 league games without a clean sheet, and recorded just one win in their last nine matches. Their attacking output also reached historic lows in several matches, including one of the weakest first-half xG performances recorded in recent seasons.
