He has been surprisingly relied upon in the early stages of this season, following a summer transfer window in which he was widely expected to depart.
A lack of genuine interest in his signature has meant the 33-year-old Brazilian stayed put - and Ruben Amorim has since made the most of his presence and experience.
Casemiro has started five league games so far and continues to play a crucial role in midfield. Amorim appears to lack confidence in others stepping into that deep-lying role, but there is an increasing sense behind the scenes that United must soon look beyond him.
The club hierarchy are already mapping out their future squad plans and the Brazilian’s long-term place is not guaranteed.
He is under contract until 2026, with a club option for an additional year, yet his salary remains one of the highest at Old Trafford.
Club insiders admit that keeping him beyond this season would only make sense if he agreed to a substantial wage reduction.
United have bold intentions over the next two transfer windows, with plans to strengthen the midfield in both January and the summer.
They want to modernise the core of the team, bringing in younger players with better mobility.
Now for Casemiro, the coming months could define how his time in England is remembered.
