The pair left the new Serie A title winners at the start of the season.
Zhang said: "When some players that the club considers important choose to leave it, it hurts.
Advertisement
Advertisement
"But everyone has their own ideas about their life, now everything is gone and they are still part of the club's history."
He also said on TikTok: "I always have the feeling that my players are the best and the ones who they work harder, if you look at many of them like Mkhitaryan, Nicol Barella, Stefan De Vrij, you feel that their life is serious, focused and simple.
"They go home after training, they pay great attention to food and drinks, and they pay attention to their family and surroundings."