The Holland midfielder has failed to match the success he enjoyed with Atalanta since his summer arrival last year.
Motta, who was sacked by Juve last week, said: “In my opinion, Koop was immediately overloaded with too many expectations. The high cost of his purchase weighed heavily. In these situations, the expectations increase and have more of an effect on the player than you’d think. But I’m sure he will be able to do better and better.
“He’s a high-level player, he’s a player that always played well for Atalanta and his national team last year. I’m convinced that when he finds balance and the expectations go to a normal level, he will return to his usual levels.
“He needs to adapt to his role in the dressing room and on the pitch, but he will always improve because he’s a very good player. He’s also a good guy, who works really hard and I’m sure he’ll give a lot to this team.”
Motta also commented on his management of Dusan Vlahovic.
He told Il Corriere della Sera: “Dusan played a lot, some say too much, but he deserved it because he always worked well.
“Sometimes he couldn’t play because he had injuries that kept him out for ten days. He’s a smart guy, capable of discussing and sharing opinions.
“The relationship with him was good, but at the same time it’s normal to feel affected depending on whether you get on the pitch or not. Dusan wasn’t happy when he didn’t play, but he always had respect for my decisions. He continued to work hard and when he came on the pitch he did his best, trying to help the team.”