Speaking to Crypto Casino, Yorke said: "It's hard to criticise Casemiro because of what he’s achieved in the game, but people should expect better from him in a Manchester United shirt.
"It really hasn’t worked out for him this season after such a good first year with the club and he isn’t getting any younger – he looks like he’s had enough and he wants a new start at another club next season.
"Jason Wilcox and the other directors at Old Trafford are going to have to have harsh conversations with these players, including Casemiro, and find out whether they really want to be here or not, or whether or not they want the manager (Erik ten Hag) here, so it’s a tough one," he continued.
"Casemiro’s a legend of the game and it’s a difficult one, but his name has very much been in the focal point of conversation over the past few months, so it’s certainly something the club need to address this summer. A decision needs to be made."