Ten Hag says his former Ajax midfielder needs to be playing regularly.
"I think Donny has to play," he conceded. "In matches he has been in the squad, so he had the opportunity.
"It was a slow start to the season as he was still recovering from physical setbacks.
"He's back now and he's doing really well in training, so if you can't give him perspective, I can see that he has to play for his career and for everything."