There's a new story at Man United. Casemiro is now seen as the team's weakest link. However, being the weakest link doesn't mean he's out of position. Casemiro is a good player, but age is catching up. He's giving his best, but he's slowing down, struggling to cover ground quickly or make swift decisions. Consequently, he's committing more fouls.
Every player has their ups and downs. Currently, he's not in top form, but it's hope that he'll bounce back.
Casemiro is a defensive midfielder, not a playmaker. Just because Ten Hag is bad at using the tools at his disposal does not mean that the tools are bad, but rather that Ten Hag is a fool. In addition, the fouls he commits do not mean that he is to blame for them, for example recently when Onana made a bad pass and Casemiro had to make a foul to save the team from a goal, it was Onana's fault and not Casemiro.