Sometimes the most basic statistics tell the story best of all. When Casemiro starts for Manchester United they win 72% of the time and lose just one in 10 games. When he doesn't start, they win 67% of the time but lose one in four.
Forget the minutiae of numbers that can explain Casemiro's impact on United and what he does so well, the bare stats don't lie. When he isn't involved United find it harder to win games and easier to lose games.
He wasn't signed in time for defeats to Brighton and Brentford, was on the bench for the mauling at Manchester City and was suspended for the defeat at Arsenal when the Gunners rained in 25 shots. You could even add in the 7-0 defeat to Liverpool, when the Brazilian midfielder may well have been absent, given how badly he played compared to the rest of this season.