Van Persie was reacting to United's defeat at Newcastle.
"You can see here's struggling there, if I'm really honest, during that interview," Van Persie told Optus Sport.
"And I get it if you're manager of Manchester United during this period of time. So he's searching for words, maybe he chose a few wrong ones there. Because as a player, what does that mean, 'sorting the players' heads out', what does that mean?
"If you're a player you're a little bit like, 'my head is fine'. 'Even though you can see the players are low in confidence, he needs to find a way to reconnect again and to get their confidence high. As a manager, when you're team is low in confidence get them up, when your team is too high in confidence, when they are becoming a little bit too much, you have to get them back to the middle again. At the moment, based on this interview, and based on what I've seen in the game, I'm not sure if he really knows how to find the buttons there."