Chelsea have equalled their highest number of red cards in a single Premier League season, matching the 2007‑08 campaign - but with 11 games still to play.
Only away at Nottingham Forest have Chelsea claimed all three points after going down to 10 men, holding on following an 87th‑minute dismissal.
Defeats against Manchester United, Brighton and Fulham can largely be attributed to red cards earlier in those matches, while Chelsea rallied well after Moises Caicedo was sent off in the home draw with Arsenal in November.
The pattern is clear - Chelsea are suffering because of their lack of discipline. They are also a team accustomed to collecting yellow cards.
They sit bottom of the Fair Play table with 86 points, having received 60 yellow cards this season. They were second-bottom last season and bottom the season before.
It is hard not to link the disciplinary record to the age profile of the squad. Chelsea have not fielded a player over the age of 28 all season and have the youngest squad in the Premier League - a profile deliberately built by the club's hierarchy.
However, Rosenior does not subscribe to youth being the main problem.
"I think youth is one thing, accountability is another," he said. "I'm accountable. I'm the head coach, I'm the manager of the team. I'm responsible for every result and every performance we have. We need players you can rely on in the moment to do their job.
"I know what we need to get there. It's not down to youth, it's down to assessing the players and identifying the ones you can rely on in difficult moments."
Rosenior also refused to single out Wesley Fofana and pointed out that the majority of red cards this season came before his appointment. Maresca himself was sent off for celebrating a last‑minute winner against Liverpool.
"Our discipline since I've come in - which is what I can speak about - has been very good," added Rosenior.