The midfielder has been so influential this season that Erik ten Hag's team often look lost without him, so he needs to sort out his discipline
Casemiro has been hailed in some quarters as Manchester United's most important signing since Eric Cantona.
It seems a little early for such a lofty comparison, even if the midfielder has enraptured the fans with his commitment and galvanised Erik ten Hag's side in his eight months at Old Trafford.
But there's one thing Casemiro and Cantona definitely have in common: red cards.
Casemiro might not have kicked any fans yet or stamped on any opponents, but in less than two months he has racked up three separate suspensions.
GettyMissing eight out of 20 matches
First, he picked up his fifth yellow card of the season in the away match against Crystal Palace in January, ruling him out of the crucial trip to Premier League leaders Arsenal, which United lost 3-2.
Then, he was sent off at home to Palace for grabbing Will Hughes' face and banned for three Premier League matches: the 2-2 draw at home to struggling Leeds, the 2-0 win away to Leeds and the 3-0 win at home to Leicester.
After being sent off against Southampton on Sunday, he is now suspended for four more matches, due to it being his second straight red card of the season.
He cannot face an in-form Fulham side in the FA Cup quarter-finals on Sunday and he is out of the trip to Newcastle and the home games with Brentford and Everton.
When he returns to domestic action in April, he will have been banned for eight out of United's previous 20 matches.
AdvertisementGettyA huge drop off in results
When the Brazilian is out, United normally suffer.
Ten Hag's side have won 72 per cent and been unbeaten in 90% of matches in which Casemiro has started.
That contrasts with winning only 53% and being unbeaten in 60% of games which he has not started.
It is a huge drop off, and the results only tell one side of the story.
United really struggled without him at home to Leicester, despite winning 3-0, and it was only when he came off the bench in the recent FA Cup tie with West Ham that the team started to click.
With the FA Cup and finishing in the top-four at stake, United cannot afford to lose the man who holds it all together for so many games.
IMAGO / NurPhotoCharm offensive doesn't work with VAR
Despite being a combative midfielder playing at the highest level for a decade, Casemiro rarely got into trouble with referees until this year.
In nine seasons with Real Madrid and one with Porto, he was never shown a straight red card.
He was dismissed for double bookings for Madrid on two occasions, against Barcelona in 2021 and Real Valladolid in 2019, and once for Sao Paulo, in 2012.
In 69 matches for Brazil, meanwhile, he has never been sent off.
As Ten Hag put it after the Southampton game: "Casemiro played over 500 games in Europe and never once got a red card. Now he has two in the Premier League."
His previous record might have something to do with the special attention he shows to referees.
A report by The Telegraph last year said Casemiro gets a member of staff to compile a dossier on each referee he is due to come up against and that he took English lessons so he could communicate better with officials.
In Spain, Casemiro's ability to escape red cards despite flying into challenges and routinely halting opposition play with fouls became a running joke.
Indeed, it is telling that both of his straight red cards with United have been given following VAR reviews.
All the charm in the world and good manners cannot reach the officials in the VAR room.
Challenges are now forensically examined and pawed over in slow-motion, making them look worse than they appear at first glance.
But that is the state of the game in 2023 and Casemiro has little choice but to adapt.
(C)Getty ImagesGive him more support
One potential reason why Casemiro has got himself into trouble this season is that he is not only United's chief fire extinguisher but also influential going forward.
He was very much used to playing the former role at Madrid but was rarely called upon in attack, partly because of the Spanish aristocrats' embarrassment of riches all over the pitch.
Now that he does not have Luka Modric, Toni Kroos or Fede Valverde by his side, Casemiro is put under more pressure with the ball at his feet.
He has risen to the challenge of playing more in this United team, showing aspects of his game not many people knew he was capable of.
But he is most effective as an enforcer, and United need to find ways to ensure that is his main task.
His plight will be helped when Christian Eriksen returns from injury and if Marcel Sabitzer, who is also currently out of action, gets more of a run of matches.