The winger has insisted he would find it hard to watch his Schalke team-mates training from the sidelines after Horst Heldt criticised him for returning to Netherlands
The Dutchman moved to the Veltins Arena from Barcelona in the summer, but has made just a handful of appearances thanks to a thigh injury, much to general manager Horst Heldt's disapproval.
"It's really bizarre how this injury has gotten to me," he told Sports-Promotion.Nl.
"First my ligament injury at Barcelona, then my tendon injury in my upper leg. In the last eighteen months, I have spent more time recovering than playing.
"I know I have to pull through and I will. But there have been moments I doubted everything.
"Of course I want to be with the guys at Schalke. Preferably, I would wish them all the best for every match, and I would be there when they play.
"That's just how I am. If you make a choice with something, you have to stick to it. With that attitude I chose a loan period at Schalke.
"But I'm sure I couldn't put up with being there and watching them in practice, I just can't put up with it.
"For my own benefit, I have to close myself off from the outside world and focus on one thing only: my recovery. That is dominating my life right now.
"How long will it take before I can play again? That's the thought I go to bed with, and wake up with. There's nothing else for me.
"The medical staff at Schalke are being updated about everything, as they should be."